SP2-433-160 Datasheet, PDF (20/27 Pages) Radiometrix Ltd – UHF SpacePort Transceiver

APPENDIX - B
Example SP2 driver subroutines for Arizona PIC16C73
SP2
D3
D2
D1
D0
TXA
TXR
RXA
RXR
figure 15: SP2 to PIC µ-C interface
PB7
PB6
PB5
PB4
HOST
PB3 ^PIC
PB2
PB1
PB0 / IRQ
Packet transfers to / from the SP2 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 SP2 to return the data bus
to inputs (default state).
;--------------------------------------------------------------------;
;
;
SP2 DRIVERS
;
;
;--------------------------------------------------------------------
;
;
HOST PROCESSOR PIC16C73 or similar
;
SP2 EQU 06 ;USE PORT B ON PIC
;
;
** Bit assignments for SP2 PORT **
;
D7 EQU 7
;Bi-Dir
D6 EQU 6
;Bi-Dir
D5 EQU 5
;Bi-Dir
D4 EQU 4
;Bi-Dir
TXA EQU 3
;INPUT
TXR EQU 2
;OUTPUT
RXA EQU 1
;OUTPUT
RXR EQU 0
;INPUT ON RB0, CAN BE CONFIGURED AS AN INTERRUPT
;
SP2_DDR 86
;Data direction register for port B (SP2)
;
;This register is in BANK 1 of the register file
;
;--------------------------------------------------------------------
;
W
EQU 0
;Accumulator as Destination
F
EQU 1
;Register File as Destination
INDF EQU 00 ;INDirect File register
Radiometrix Ltd, SP2 data sheet
page 20