Radiometrix Ltd, RPC3G

page 21

Example RPC3G driver subroutines for Motorola 68HC11

D0

D1

D2

D3

TXA

TXR

RXA

RXR

PC3

PC2

PC1

PC0

PC7

PC6

PC5

PC4

RPC3G

HC11

HOST

IRQ

Packet transfers to / from the RPC3G are best handled in the host by two subroutines :- OUT_BYTE &

IN_BYTE

Additionally LISTEN_BUS is called on completion of a packet transfer to the RPC3G to return the data bus

to inputs (default state).

*********************************************************************

*

* CPU REGISTER EQUATIONS

*

*********************************************************************

*

*This section contains a few of the necessary register equations used

*in the example subroutines.

PORTC

EQU

$1003

;ADDRESS OF RPC3G PORT

DDRC

EQU

$1007

;DATA DIRECTION REGISTER PORT-C

* Port-C7 = RX-accept OUTPUT

* Port-C6 = RX-request INPUT

* Port-C5 = TX-accept INPUT

* Port-C4 = TX-request OUTPUT

* Port-C3 = RPC3G data bit-3

* Port-C2 = RPC3G data bit-2

* Port-C1 = RPC3G data bit-1

* Port-C0 = RPC3G data bit-0

figure 17: RPC3G to HC11