SBC2000-332

General Information

The SBC2000-332 is a high performance, 32 bit, low power single board computer. Onboard peripherals support external keypad, alphanumeric LCD, audio transducer and onboard battery backable Real Time Clock. Eight TPU channels, 6 interrupt inputs and 4 TPU digital I/O lines are available on the Bus connector. Onboard memory consists of socketed byte wide boot ROM, word wide flash and word wide battery backable RAM.

In addition to the microprocessor memory, a serial EEPROM can store setup and configuration parameters. Frequently updated process parameters may be stored in additional battery backed RAM in the serially addressed Real Time Clock. The basic onboard functions can be expanded via external bus, VAST bus and one reconfigurable asynchronous serial channel. The external bus can be 8 or 16 bits wide.

Battery Backed RAM, "BB"

Onboard RAM may be battery backed from an external battery if "BB" is installed between pins 1-2. If battery backed RAM is not required, install "BB" between pins 2-3. Disabling the battery backed RAM (pins 2-3) will result in lowest power consumption, especially when the device is in the hibernate low power mode.

The Real Time Clock and its internal RAM will remain connected to the standby power source whether or not the main RAM is enabled for battery backup.

The factory setting is battery backing disabled (pins 2-3 shorted).

Watchdog, "WD"

The external 1.5 second watchdog timer is defeated by not installing the WD jumper.

The watchdog will bring the SBC2000-188 out of the power-down mode if the WD jumper is installed between pins 1-2.

The watchdog must be reset by a VAST transfer every 1.5 seconds if the jumper is placed between pins 2-3. If this is not done the SBC2000-188 will reset. The factory setting is no jumper installed.

1 Meg ROM, "1MROM"

The "1MROM" jumper must be installed if a 1 megabyte, 27C080 device is used in the boot ROM socket, otherwise, the jumper must be removed. The factory setting is not installed.

Hibernate "HIB"

The Hibernate jumper is used to allow timed powerdowns with a self-switching power supply. Calls to hibernate() in the Vesta C Library or Vesta Basic will shut down the power supply for a preprogrammed interval if a self switching power supply is present. If you are not using a self-switching supply, installing this jumper will allow you to enter the equivalent of sleep mode for the duration of the power down interval. See the Power Modes section below for descriptions of sleep and hibernate modes.

If neither a self-switching power supply or the hibernate jumper are installed and you enter hibernate mode the SBC2000 will shut down until it is manually reset.

"485"

The "485" adaptor connector must have a jumper installed on pins 5-6 unless the optional RS-485 adaptor module is plugged into this connector. If no jumper or adaptor is installed, the SBC2000 will be unable to receive data from the COM port. This jumper is installed at the factory.

Power Modes

Normal

Normal operation will consume approximately 100 mA of power. The SBC2000-332 requires a single 5 VDC supply rated at 200 mA. Lower power modes are supported. Battery backup current to the onboard RAM and RTC is supplied via pin 3 of the PWR connector and is not included in the power consumption figures. The RTC will consume approximately 10 to 20 uA of current during backup. Battery backup of RAM can be defeated with the "BB" jumper.

Nap

The nap mode of operation will reduce the power consumption. During nap mode, all peripherals are active. Normal mode will resume upon the application of any internal or external interrupt (including the UART.) Nap mode can be entered via a call to to the nap() procedure in the Vesta C Library or Vesta Basic.

Sleep

The sleep mode of operation shuts down the internal clocks, thus further reducing the power consumption. Normal execution will resume upon the application of any interrupt, however, the TPU and the UART are not active during sleep mode and so cannot be used to generate the waking interrupt. Sleep mode can be entered via a call to the sleep() function in the Vesta C Library or Vesta Basic.

Hibernate

Hibernate mode provides the lowest power consumption of all low power modes. Hibernate mode also has a software programmable low power time interval parameter (See the Vesta Basic or Vesta C library manual for more information). If you are using a self-switching power supply, the supply is shut down for the duration of the low power interval. In this state power is consumed only by battery backed components through the Vstby pin (pin 4) of the power connector. Note that when power is restored, it is similar to a board reset in that it will restart your code from the beginning.

If you are not using a self-switching supply then the HIB jumper should be installed. In this configuration, hibernate mode is identical to sleep mode, except that the board will wake up after the programmed power down interval. Your code will continue execution where it left off.

If you have not installed either a self-switching supply or the HIB jumper, entering hibernate mode will put the SBC2000 into a mode much like sleep mode, except that only a board reset will wake it up.

Hibernate mode can be entered via a call to the hibernate() procedure in the Vesta C Library or Vesta Basic. The power down interval is specified in the call to hibernate().

Power Mode Comparison

The following data is taken with an SBC2000-188 operating at 20 MHz with 128 Kbytes of RAM, 128 Kbytes of ROM, 4k bytes of EEPROM, and a Real Time Clock. Current is monitored through the power input (PWR connector pin 2) and the standby power input (PWR connector pin 4). These figures are with the LED illuminated (it adds about 5 mA).

Memory on the SBC2000-332

SBC2000-331 Memory Map

The memory map of the SBC2000-332 spans 10 megabytes. The memory map below shows the address in megabytes (Meg), the applicable device, the data path size in bits (DP), the number of wait states (WS) and the appropriate strobes to use for bus devices. If devices smaller than 1 megabyte are installed, images will exist within the device's one megabyte range.

The first 4 megabytes of memory space is physically located on the SBC2000-332. The next four megabytes are available on the 16 bit bus connector using the MEMW* and MEMR* strobes. Devices mapped in this range must activate DSACK0* (low) to terminate the bus cycle. The next megabyte is mapped as 8 bit bus memory using MR* and MW* with 250 ns access time requirements. The final megabyte is mapped as 8 bit IO space using IOR* and IOW* with 500 ns access time requirements .

Boot ROM

The SBC2000-332 boot ROM is a socketed byte wide ("x 8") device. The boot ROM is active for addresses 00 0000 to 0F FFFF (or the first megabyte) of address space. The access time requirement for boot ROM is tabulated below.

Boot ROM can be 128k, 256k, 512kor 1M bytes. Typical part numbers are 27C010, 27C020, 27C040 and 27C080 respectively. All Vesta ROMmed languages use one wait state in the boot ROM.

Battery Backable RAM

RAM is available in three sizes: 64Kbyte, 256Kbyte, and 1Mbyte.

The onboard RAM may be battery backed by connecting the positive terminal of an external 3.5 to 5.0 Volt battery to pin 4 of the power connector. The minus terminal of the battery is grounded (pin 1 of the power connector).

The specification of standby current for RAM devices varies widely. Typical backup current is less than 10 uA. However, worst case specification currents can be as high as 2 mA. A "typical worst case" current is 100 uA in the battery backed state. A battery consisting of 3 "AA" cells (nominally 1 Ahr, 4.5 Volts) will backup the RAM for 10,000 hours.

Current from the external battery is supplied through an onboard diode. This prevents the SBC2000-332 from overcharging any battery attached.

Flash

Flash memory is available in sizes ranging from 64Kbyte to 1Mbyte.

Flash memory is accessible as 16 bit word read or write. Bytes may not be written. Flash memory is similar to EPROM in that "1" bits may be written as "0" but a "0" cannot be written to a "1" until the device is erased. Although any 16 bit word is accessible as a write operation, erasing must be done on a sector basis. Vesta software drivers organize the different sized physical sectors into 64k byte logical sectors. Erasing a sector typically takes less than 2 seconds, but may take as long as 30 seconds.

The flash memory on the SBC2000-332 is rated at a minimum of 100,000 write cycles.

EEPROM

The serial EEPROM is designed to hold infrequently updated operational parameters such as last operator settings or calibration factors. EEPROM is available in various sizes ranging from 128 bytes to 8K bytes. Unlike flash, data can be modified on a byte by byte basis. The device is rated for 1,000,000 cycles.

Relative Speed

The relative speed of execution of your program depends on the size of the data path (8 or 16 bits) and the number of wait states. The 8 bit wide data bus on the boot ROM is not as fast as the 16 bit wide data bus on RAM or Flash. Flash will require one or two wait states.

The table below shows the relative amount of time spent to access memory.

The actual differences are not as prominent as the table suggests. The times shown are only the times needed to get the data from memory and does not include the time needed to operate on the data.

Indicators

LED

The single LED on the SBC2000-332 indicates the state of the MODCK line from the 68332 processor. The LED is illuminated when MODCK is low.

MODCK is used to implement "push to talk" (PTT) logic when an RS-485 adaptor is installed on the COM 485 connector. With an adaptor installed, an illuminated LED indicates receive mode. If no such adaptor is installed, you are free to use the LED however you like. It can be controlled by manipulating MODCK directly, or by toggling PTT via the ptt() or comm() procedures in the Vesta C library or in Vesta Basic.

Interrupts

There are 7 interrupt lines available on the SBC2000-332. They are used according to the following table.

Connector

Power Connector

The power connector supplies primary power at ground and +5. Standby power to the RTC and RAM is supplied via pin 4. Standby power is 3.5V < Vstby <5.0V. The PWRON* signal allows the SBC2000-332 to switch on and off its own main power if a self-switching supply is installed. PWRON* will go low to turn on an external power supply.

DEV Connector

The Development connector supplies RS-232 level signals at up to 19.2k Baud from a software UART supported by the TPU. Note that there is no output from this port unless it is connected to valid RS-232 levels, as from another serial port.

COM Connector

The Communications connector supplies RS-232 signals at up to 115k Baud directly from the integral CPU UART. Note that there is no output from this port unless it is connected to valid RS-232 levels, as from another serial port.

VAST Connector

The Vesta Addressable Synchronous Transfer connector allows synchronous serial bus expansion to VAST peripherals.

LCD Connector

TheLCD is interfaced in the "4-bit" mode. The LCD contrast voltage, Vo, can be adjusted using the onboard trimpot (R5) for any voltage between +5 and ground.

Keypad Connector

The KEYPAD is a standard 4 x 4 matrix type Mating connector is Molex 50-57-9008 and 16-02-0097 .

Serial Expansion Connector

The "485" connector allows attachment of optional serial adaptor boards to convert the "COM" port to RS-485, RS-422 or IrDA standard. Normally, pins 5 to 6 are jumpered to activate RS-232 levels on the "COM" connector.

Background Debug Mode Connector

The Background Debug Mode connector allows debugging during C development.

Beep Connector

The BEEP connector provides easy access to TPU channel 6, used by default for audio tone generation. This line is also used as the BAUDCLK signal if the optional IrDA adaptor is connected to the COM 485 connector. This function may preclude the use of TPU6 as an audio source.

External Bus Connector, J1AB

The external bus connector is an extension of the microprocessor data, address and control bus. In addition, unused direct control signals are available. If you wish to use or reconfigure any microprocessor I/O signals the Motorola 68332 SIM manual should be consulted.

Mounting holes and J1AB, J2CD bus connectors are per PC/104 standard. The signals present on connectors J1AB and J2CD do not conform to the PC/104 standard. However, the data bus, address bus and read/write strobes do conform to the standard, allowing the SBC2000-332 to work with many PC/104 modules.

A maximum of 4 external peripherals may be attached to J1AB or J2CD.

External Bus Connector, J2CD

SBC2000-332 Mating Connectors

SBC2000-332 Dimension Drawing
- Dimensions are in inches.

SBC2000-332 Schematic, page 1

SBC2000-332 Schematic, page 2