Wildcat (BL2000) User's Manual

> ## 3. Subsystems

> Chapter 3 describes the principal subsystems for the BL2000.

> · Switching Between Program Mode and Run Mode
> · BL2000 Subsystems
> · Digital I/O
> · Relay Outputs
> · Serial Communication
> · A/D Converter Inputs
> · D/A Converter Outputs
> · Memory
> · External Interrupts

> ### 3.1 Switching Between Program Mode and Run Mode

> The BL2000 is automatically in Program Mode when the programming cable is attached, and is automatically in Run Mode when no programming cable is attached. See Figure 5.

> Figure 5. BL2000 Program Mode and Run Mode Set-Up

> #### 3.1.1 Detailed Instructions: Changing from Program Mode to Run Mode

> 1. Disconnect the programming cable from header J5 of the BL2000.
> 2. Reset the BL2000 by unplugging the AC adapter, then plugging it back in, or by momentarily connecting the reset pin on screw terminal header J2 to ground.

> The BL2000 is now ready to operate in the Run Mode.

> #### 3.1.2 Detailed Instructions: Changing from Run Mode to Program Mode

> 1. Attach the programming cable to header J5 of the BL2000.
> 2. Reset the BL2000 by unplugging the AC adapter, then plugging it back in, or by momentarily connecting the reset pin on screw terminal header J2 to ground. Alternatively, you may press <Ctrl-Y> on your PC if Dynamic C is running.

> The BL2000 is now ready to operate in the Program Mode.

> ### 3.2 BL2000 Subsystems

> Figure 6 shows the Rabbit-based subsystems designed into the BL2000.

> Figure 6. BL2000 Rabbit-Based Subsystems

> Table 2 lists the Rabbit 2000 parallel ports and their use in the BL2000.

> Table 2. Use of Rabbit 2000 Parallel Ports
> Port | I/O | Signal | Output Function State
> PA0 | Output | OUT0/RELAY/LED_DS4 | Off
> PA1 | Output | OUT1/LED_DS5 | Off
> PA2 | Output | OUT2/LED_DS6 | Off
> PA3 | Output | OUT3/LED_DS7 | Off
> PA4 | Output | OUT4 | Off
> PA5 | Output | OUT5 | Off
> PA6 | Output | OUT6 | Off
> PA7 | Output | OUT7 | Off
> PB0 | Input | IN6 | N/A
> PB1 | Input | CLKA | N/A
> PB2 | Input | IN7 | N/A
> PB3 | Input | IN8 | N/A
> PB4 | Input | IN9 | N/A
> PB5 | Input | IN10 | N/A
> PB6 | Output | RS485_EN | Off
> PB7 | Output | UPGOOD | Off
> PC0 | Output | TXD RS-485 | Serial Port D | Inactive high
> PC1 | Input | RXD RS-485 | N/A
> PC2 | Output | RTS/TXC RS-232 | Serial Port C | Inactive high
> PC3 | Input | CTS/RXC RS-232 | N/A
> PC4 | Output | TXB RS-232 | Serial Port B | Inactive high
> PC5 | Input | RXB RS-232 | N/A
> PC6 | Output | TXA Programming Port | Serial Port A | Inactive high
> PC7 | Input | RXA Programming Port | N/A
> PD0 | Output | DAC-ADC_SK | On
> PD1 | Output | DAC-ADC_SDI | On
> PD2 | Input | RTL-ADC_SDO | N/A
> PD3 | Input | RTL_SK | N/A1
> PD4 | Output | RTL_SDI | On
> PD5 | Output | /DAC0_CS | Inactive high
> PD6 | Output | /DAC1_CS | Inactive high
> PD7 | Output | /ADC_CS | Inactive high
> PE0 | Output | OUT8 | Off
> PE1 | Output | OUT9 | Off
> PE2 | Input | IN0 | N/A
> PE3 | Input | IN1 | N/A
> PE4 | Input | IN2 | N/A
> PE5 | Input | IN3 | N/A
> PE6 | Input | IN4 | N/A
> PE7 | Input | IN5 | N/A

> 1 PD3 is an output (and is on) for the BL2020 and the BL2030.

> The BL2000 pinouts are shown in Figure 7.

> Figure 7. BL2000 Pinouts

> #### 3.2.1 Headers and Screw Terminals

> All BL2000 models are equipped with 1 × 12 screw terminal strips (J2, J4, J8, and J9) and a 2-pin power jack (J7). The BL2000 and BL2010 also have the RJ-45 Ethernet jack (J6).

> There is provision on the circuit board to accommodate 2 × 17 male headers instead of the 1 × 12 screw terminal strips supplied, and 2 × 17 male headers can be factory-installed by special request for volume orders. Please contact your Z-World Sales Representative at +1(530)757-3737 for more information.

> #### 3.2.2 Power Supply Pins

> Instead of connecting an AC adapter to the power supply jack, J7, the input power supply (9 V to 40 V DC) may be connected to pins 12 and 11 on header J2 (see Figure 7).

> Pin 12 on header J9 is normally GND by factory default, but may be changed to Vcc by removing resistor R160 and installing resistor R161. See Appendix C, "Power Supply," for more information on this configuration and for information on backup-battery options.

> ### 3.3 Digital I/O

> #### 3.3.1 Digital Inputs

> The BL2000 has 11 digital inputs, IN0-IN10, each of which is protected over a range of -36 V to +36 V. The inputs are factory-configured to be pulled up to +5 V, but they can also be pulled down by moving the surface-mounted jumper at JP6 as shown in Figure 8.

> Figure 8(a). BL2000 Digital Inputs [Pulled Up—JP6(1-2) connected]

> Figure 8(b). BL2000 Digital Inputs [Pulled Down—JP6(2-3) connected]

> Figure 8(c). Example of Logic Gate Driving BL2000 Digital Input

> The actual switching threshold is approximately 2.40 V for channels IN0-IN10. Anything below this value is a logic 0, and anything above is a logic 1.

> The A/D converter inputs can be used as additional digital inputs using the parameters specified for the digIn software function call. The default threshold for channels IN11-IN21 is also set to 2.40 V, but may be changed by adding two lines to your program as discussed for the digIn software function call.

> #### 3.3.2 Digital Outputs

> The BL2000 has 10 digital outputs, OUT0-OUT9, each of which can either sink or source up to 200 mA, depending on how the outputs are configured.

> Each output can be configured individually as either a sinking or a sourcing output as shown in Figure 9. The outputs can be pulled as a group to Vcc, +K, or GND through 27 kW resistors. Tie the outputs high to either Vcc or +K when using the outputs as sinking outputs (via 0 W resistors at R32 or R35 respectively), or tie the outputs to GND via R34 when using the outputs as sourcing outputs. +K is an externally supplied voltage of up to 40 V DC, and is used primarily in combination with current sourcing outputs, and must also be connected to an external supply when an inductive load is conncted to a sinking output.

> NOTE | Remove the 27 kW resistors (R143-R150) from the output circuits if no pull-up/down is required to avoid leakage between the outputs. These resistors are located on the bottom side of the BL2000 board above the solder points for screw terminal header J9.

> Figure 9. BL2000 Digital Outputs

> The locations of the output pull-up/pull-down select resistors R32, R34, and R35 are shown in Figure 10.

> Figure 10. Locations of Resistors R32, R34, and R35

> All BL2000 models are factory-configured with sinking outputs and pull-up resistors tied to Vcc via a 0 W resistor at R32. Large-volume orders can be factory-configured to your individual needs. Contact your Z-World Sales Representative at +1(530)757-3737 for more information.

> ### 3.4 Relay Outputs

> Figure 11 shows the BL2000 relay contact connections. A diode across the coil provides a return path for inductive spikes, and snubbers across the relay contacts protect the relay contacts from inductive spikes.

> Figure 11. BL2000 Relay Output Contact Connections

> The relay is driven by PA0, which is the same Rabbit 2000 parallel port that drives OUT0 and LED DS4. OUT0 therefore works in parallel with the relay output.

> ### 3.5 Serial Communication

> The BL2000 has one RS-232 serial channel (with RTS/CTS) or two RS-232 (3-wire) channels, one RS-485 serial channel, and one CMOS serial channel. The RS-232 channel(s) are configured with the serMode software function call. Table 3 summarizes the options.

> Table 3. Serial Communication Configurations
> Mode | Serial Port
> B | C | D
> 0 | RS-232, 3-wire | RS-232, 3-wire | RS-485
> 1 | RS-232, 5-wire | CTS/RTS | RS-485

> All four serial ports operate in an asynchronous mode. An asynchronous port can handle 7 or 8 data bits. A 9th bit address scheme, where an additional bit is sent to mark the first byte of a message, is also supported. Serial Port A can be operated alternately in the clocked serial mode. In this mode, a clock line synchronously clocks the data in or out. Either of the two communicating devices can supply the clock. The BL2000 series boards typically use all four ports in the asynchronous serial mode. Serial Ports B and C are used for RS-232 communication, and Serial Port D is used for RS-485 communication. The BL2000 uses an 11.0592 MHz crystal, which is doubled to 22.1184 MHz. At this frequency, the BL2000 supports standard baud rates up to a maximum of 230,400 bps.

> #### 3.5.1 RS-232

> The BL2000 RS-232 serial communication is supported by an RS-232 transceiver, U1. U1 provides the voltage output, slew rate, and input voltage immunity required to meet the RS-232 serial communication protocol. Basically, the chip translates the Rabbit 2000's CMOS/TTL signals to RS-232 signal levels. Note that the polarity is reversed in an RS-232 circuit so that a +5 V output becomes approximately -10 V and 0 V is output as +10 V. U1 also provides the proper line loading for reliable communication.

> RS-232 can be used effectively at this baud rate for distances up to 15 m.

> #### 3.5.2 RS-485

> The BL2000 has one RS-485 serial channel, which is connected to the Rabbit 2000 Serial Port D through U8, an RS-485 transceiver. U8 supports the RS-485 serial communication protocol. The chip's slew rate limiters provide for a maximum baud rate of 230,400 bps, which allows for a network of up to 300 m (or 1000 ft). The half-duplex communication uses the Rabbit 2000's PB6 pin to control the transmit enable on the communication line.

> The BL2000 can be used in an RS-485 multidrop network. Connect the 485+ to 485+ and 485- to 485- using single twisted-pair wires (nonstranded, tinned) as shown in Figure 12. Note that a common ground is recommended.

> Figure 12. Multidrop BL2000 Network

> The BL2000 comes with a 220 W termination resistor and two 681 W bias resistors installed and enabled with jumpers across pins 1-2 and 3-4 on header JP1, as shown in Figure 13.

> Figure 13. RS-485 Termination and Bias Resistors

> The bias and termination resistors in a multidrop network should only be enabled on both end nodes of the network. Disable the termination and bias resistors on the intervening BL2000 units in the network by removing both jumpers from header JP1.

> #### 3.5.3 Programming Port

> The BL2000 has a 10-pin programming header labeled J5. The programming port uses the Rabbit 2000's Serial Port A for communication. The Rabbit 2000 startup-mode pins (SMODE0, SMODE1) are presented to the programming port so that an externally connected device can force the BL2000 to start up in an external bootstrap mode.

> NOTE | Refer to the Rabbit 2000 Microprocessor User's Manual for more information related to the bootstrap mode.

> The programming port is used to start the BL2000 in a mode where the BL2000 will download a program from the port and then execute the program. The programming port transmits information to and from a PC while a program is being debugged.

> The BL2000 can be reset from the programming port via the /EXT_RSTIN line.

> The Rabbit 2000 status pin is also presented to the programming port. The status pin is an output that can be used to send a general digital signal.

> #### 3.5.4 Ethernet Port

> Figure 14 shows the pinout for the Ethernet port (J6). Note that there are two standards for numbering the pins on this connector—the convention used here, and numbering in reverse to that shown. Regardless of the numbering convention followed, the pin positions relative to the spring tab position (located at the bottom of the RJ-45 jack in Figure 14) are always absolute, and the RJ-45 connector will work properly with off-the-shelf Ethernet cables.

> Figure 14. RJ-45 Ethernet Port Pinout

> RJ-45 pinouts are sometimes numbered opposite to the way shown in Figure 14.

> The transformer/connector assembly ground is connected to the BL2000 printed circuit board digital ground via a 0 W resistor "jumper," R1, as shown in Figure 15.

> Figure 15. Isolation Resistor R1

> The factory default is for the 0 W resistor "jumper" at R1 to be installed. In high-noise environments, it may be useful to ground the transformer/connector assembly directly through the chassis ground. This will be especially helpful to minimize ESD and/or EMI problems. Once you have removed the 0 W resistor "jumper," R1, use a ring lug to attach the BL2000 to the chassis ground, thereby grounding the transformer/connector assembly.

> A convenient position for the ring lug has been provided at the top-left mounting screw hole near the RJ-45 jack as shown in Figure 16.

> Figure 16. Recommended Location for Ring Lug

> ### 3.6 A/D Converter Inputs

> The single 14-channel A/D converter used in the BL2000 has a resolution of 12 bits (models BL2000 and BL2020) or 10 bits (models BL2010 and BL2030). Eleven of the 14 channels are available externally, and three are used internally for the reference voltages: 4.096 V (Vref), 2.048 V (Vref/2), and Analog Ground. These internal voltages can be used to check the functioning of the A/D converter.

> The A/D converter only measures voltages between 0 V and the applied reference voltage. Therefore, each external input has circuitry that provides scaling and buffering. The first four external inputs are scaled and buffered to provide the user with an input impedance of 1 MW and a range of -10.24 V to +10.24 V. The remaining five or seven inputs are not buffered, but are scaled to provide inputs that can range from 0 V to +49 V.

> Figure 17 shows the buffered A/D converter inputs.

> Figure 17. Buffered A/D Converter Inputs

> The op-amp is powered from the +V supply. The 1 MW and 200 kW resistors set the gain (scale factor), which is 5 in this case. This results in a dynamic input range of 5 × 4.096 V or 20.48 V. The center point of this range is set by the 1.707 V reference voltage. With the reference set to 1.707 V, the center point is at 0 V and the input voltage can range from
> -10.24 V to +10.24 V. To maintain the best accuracy, the input range should be limited to
> -10.0 V to +10.0 V.

> The five or seven unbuffered inputs have an impedance of 12 kW and a scale factor of 0.0833, which provides for an input voltage range of 0 V to 49.15 V. Accuracy is maintained over the specified voltage range from 0 V to 48 V DC.

> The analog inputs can also be used as digital inputs when required. In this case a lower quality 10-bit D/A converter can be used, and the software would assign a 1 or 0 to a voltage based on whether it is above or below a particular threshold. See the digIn function description for more information.

> ### 3.7 D/A Converter Outputs

> Figure 18 shows the analog voltage reference circuit.

> Figure 18. Analog Reference Voltages

> This circuit generates the 4.096 V reference voltage, which is used by the A/D converter and optionally by the two D/A converters. This sets the operating range of the A/D converter and the D/A converters (0-4.096 V). To use the full accuracy of the A/D converter and the D/A converters, this voltage must be accurate to the same degree.

> Under normal operation, the 453 W resistor is not installed. The reference zener diode in combination with the 100 W resistor form a shunt regulator. The 4.096 V reference voltage then feeds the A/D converter, the D/A converters, and the voltage divider composed of the 10 kW and the 14 kW resistors. The voltage divider generates a second reference voltage of 1.707 V to feed the four op-amps for the buffered A/D converter inputs.

> The reference voltage can be ratiometric rather than absolute. This is done by removing the zener diode and installing the 453 W resistor. With this arrangement, the reference voltages follow changes in the power supply voltages Vcc and V+, which is a filtered version of Vcc. This type of measurement circuit is preferred by some customers whose sensors are powered from the Vcc supply and hence the outputs track Vcc.

> A jumper on header JP3 allows the D/A converters to be powered either from the 4.096 V reference (factory default) or from the analog supply +V. The D/A converters use their power source also as the reference input, so normally powering the D/A converters from the more accurate 4.096 V reference is best. However, should a customer desire more dynamic range (0-5 V rather than 0-4.096 V), the jumper across JP3 can be set to power the D/A converters from +V. When powered from the +V supply, the outputs of the D/A converters will always be ratiometric, independent of whether the zener diode is installed.

> Only the BL2000 and the BL2020 models are stuffed with D/A converters. The D/A converters provide only a voltage output. This means that in order to maintain the maximum accuracy of the D/A converters, only a small amount of current should be drawn from the D/A converter output (of the order of µA).

> With D/A converters installed, the user has the option of using an unbuffered A/D converter input to read the output of a D/A converter or one of the two fixed voltages +V or Vcc. The standard BL2000 configuration is for A/D converter channels 9 and 10 to monitor D/A converter channels 0 and 1 respectively.

> Figure 19 shows the D/A converter outputs with buffer amplifiers, which may be used to increase the D/A converter output voltage range to 0 V to +10 V.

> Figure 19. D/A Converter Outputs

> ### 3.8 Memory

> Section A.3, "Jumper Configurations," shows where the 0 W surface-mounted "jumpers" described in this section are found.

> #### 3.8.1 SRAM

> The BL2000 is designed to accept 128K to 512K of SRAM packaged in an SOIC case.

> The standard models come with 128K of SRAM. Table 4 lists the jumper settings for the jumpers used to set the SRAM size. The "jumpers" are 0 W surface-mounted resistors.

> Table 4. Memory Jumper Selections
> SRAM (JP5) | Flash Memory (JP4)
> 1-2 | 128K | 1-2 | 128K/256K
> 2-3 | 512K | 2-3 | 512K

> #### 3.8.2 Flash Memory

> The BL2000 is also designed to accept 128K to 512K of flash memory packaged in a TSOP case.

> The BL2000 comes with one 256K flash memory. Table 4 lists the jumper settings for the jumpers used to set the SRAM size. The "jumpers" are 0 W surface-mounted resistors.

> NOTE | Z-World recommends that any customer applications should not be constrained by the sector size of the flash memory since it may be necessary to change the sector size in the future.

> A Flash Memory Bank Select jumper configuration option exists at JP2 with 0 W surface-mounted resistors. This provision allows the code space in the flash memory to be split in half so that one flash memory chip can emulate the two flash memory chips found on some Z-World single-board computers.

> NOTE | Only the Normal Mode (pins 1-2 connected at JP2), which corresponds to using the full code space, is supported at the present time.

> ### 3.9 External Interrupts

> The BL2000 does not normally come configured to support external interrupts. However, should this functionality be required, it is possible to modify the board to support one external interrupt. To gain the external interrupt requires giving up the use of two of the 11 digital input lines, IN2 and IN3, and adding a 1 kW resistor at position R155 as shown in Figure 20. The external interrupt is then available on pin 2 of header J8.

> Figure 20. Use of Rabbit 2000 External Interrupt

> Figure 21 shows the location of R155.

> Figure 21. Location of R155 (Add for External Interrupt)

> NOTE | Refer to Technical Note TN301, Rabbit 2000 Microprocessor Interrupt Problem, for more information. The modification given here for the BL2000 takes into account the workaround fix recommended in TN301.

Z-World http://www.zworld.com Voice: (530) 753-3737 FAX: (530) 753-5141 sales@zworld.com