MODEL 68HC11 CPU BOARD
FEATURES
*REPLACES 6802 CPU BOARD IN THE 170E CONTROLLER *FOUR ACIAS SUPPORTED PER CALTRANS SPECIFICATION *EMPLOYS 9.8 MHZ MPU CLOCK FREQUENCY *MEMORY COMPLEMENT OF 32K NOVRAM (WITH OPTIONAL BATTERY BACKED CLOCK) AND TWO SEGMENTS OF 32K EPROM BANKSWITCHABLE *EIGHT POSITION FEATURE AND LOCATION SWITCHES *LED TO INDICATE ACCURATE OPERATION *+12, -12, AND +5 VOLT SUPPLIES ARE TRANSORB PROTECTED ON THE CPU BOARD *EXTERNAL AND INTERNAL MEMORY MAPS JUMPER SELECTABLE DESCRIPTION The Model 68HC11 CPU Board is designed to replace the 6802 CPU Board used in the current 170E Controllers. APPLICATIONS With the end-of-life of the 6802 MPU the Model 68HC11 CPU Board will allow the 170E to continue in all applications presently in use. Software is upwards compatible with but a few minor additions. The 68HC11F1 MPU has greater capability than the 6802, allowing more complex applications. FEATURES The 68HC11 code is upwards compatible with the 6802 MPU. The 68HC11 CPU Board has the identical 6850 communications chips, uses the same RESET, NMI, and start up circuitry. The 68HC11 CPU provides a 32 pin ZIF socket allowing either a 32K x 8 bit or 128K x 8 bit EPROM. If a 128K x 8 is used, a bank switch circuit is provided to make an additional 32K x 8 block available. 32K x 8 bit of NOVRAM is available with an optional battery backed clock/calendar located in the top most 8 bits. An EXT/INT jumper allows for 4K x 8 bit of external memory to be accessed. Feature and Location switches normally located on the 412C Program Module have been added to the 68HC11 CPU. There is a software controlled LED located at the front of the board that may be used for any desired indication. The +12, -12, and +5V power supplies are all protected by energy absorbing, voltage clamp devices. MPU The MPU chip shall be an Motorola 68HC11F1 operating at a crystal frequency of 9.8 mHz. EPROM
The 68HC11 CPU Board contains a 32 pin ZIF socket. Either a 32K x 8 bit 27C256 (28 pin) or 128K x 8 bit 27C010 (32 pin) chip may be installed. If the 128K x 8 bit chip is installed the upper 64K may be accessed by a write to location $7002 which sets address bit A16 to +5. The status of A15 may be read at bit 6 (D5) of the CPU status register.
NOVRAM
The 68HC11 CPU Board has a 32K x 8 bit NOVRAM, which in the INT mode provides locations $0000-$6FFF and $7600-$7FFF to the program developer. If the optional DALLAS DS1744 chip is installed then locations $7FF8-$7FFF are mapped to the clock/calendar. If the EXT position is set by jumper, then locations $6000-$6FFF access a remote Dual port Ram. The status of the EXT/INT jumper shall be read at bit five (D4) of the CPU status register.
COMMUNICATION
Per CALTRANS specification, four ACIA chips are located on the 68HC11 CPU Board. The ACIA chips are 6850 devices and operate at baud rates of 1200, 2400, 4800, 9600, and 19200 baud.
FEATURE & LOCATION SWITCHES
Two 8 bit slide switches are located at the front of the 68HC11 CPU Board. The FEATURE switch shall be addressed at location $700A and the LOCATION switch at location $7000.
LED INDICATOR
An LED indicator is located at the front of the 68HC11 CPU and is driven on by writing a "1" to Port G bit 3 (D2).
68HC11 MEMORY MAP
| LOCATION | SIZE | DESCRIPTION |
| $0000-$5FFF | 24K | 170/CPU RAM |
| $6000-$6FFF | 4K | EXT/INT SELECTABLE RAM |
| $7000-$73FF | 1K | 68HC11 INTERNAL RAM/CONFIG REGISTERS |
| $7000-$705F | 96 | CONFIGURATION REGISTERS |
| $7000 | 1 | BANK SELECT/PORT G BIT 1 |
| $7002 | 1 | STATUS/LED INDICATOR ON=”1” |
| $700A | 1 | LOCATION SWITCH |
| $7060-$73FF | 928 | 68HC11 INTERNAL RAM |
| $7400-$75FF | 512 | EXTERNAL I/O |
| $7400 | 1 | DTA MINUTES |
| $740F | 1 | DTA SECONDS |
| $7401-$740A | 10 | I/O |
| $7410-$7417 | 8 | ACIA |
| $7500-$7507 | 8 | DUAL PORT SEMAPHORES(EXT MEMORY) |
| $75FF | 1 | 60 HZ RESET/CPU STATUS REG |
| $7600-$7FFF | 2K | 170/CPU RAM |
| $7FF8-$7FFF | 8 | CLOCK/CALENDAR |
| $8000-$FFFF | 32K | EPROM |