Specifications

EPC-8A Hardware Reference

Table A-4. Counter-Timer functions: RadiSys R400EX emulating 8254 of PC⁄AT

I/O Addr Functional group Usage

040 Timer Counter 0

041 Counter 1

042 Counter 2

043 Control (W)

Table A-5. Keyboard Port: RadiSys R400EX emulating 8742 of PC/AT

I/O Addr Functional group Usage

060 Keyboard controller Data I/O register

061 Port B R400EX Miscellaneous control bits

064 Keyboard controller Command/status register

Table A-6. Time-of-Day Clock: RadiSys R400EX emulating MC146818 of PC⁄AT

I/O Addr Functional group Usage

070 Real-time clock RTC index reg / R400EX NMI enable

071 RTC data register

0 seconds

1 seconds alarm

2 minutes

3 minutes alarm

4 hours

5 hours alarm

6 day of week

7 date of month

8 month

9 year

A status A

B status B

C status C

D status D

ERAM

...

3F RAM

Table A-7. DMA Page Registers: RadiSys R400EX emulating 74LS612 of PC/AT

I/O Addr Functional group Usage

080 Phoenix BIOS status information

081 DMA Channel 2 page register

082 Channel 3 page register

083 Channel 1 page register

087 Channel 0 page register

089 Channel 6 page register

08A Channel 7 page register