HD64570 Datasheet, PDF (346/469 Pages) Hitachi Semiconductor – Serial Communications Adaptor

Start
Read ST1
(ACC ← ST1)
Clear interrupt
source bit
(ST1 ← ACC)
Analyze interrupt source
Process interrupt
Issue EI instruction
ACC: Accumulator
ST1: Status register 1
Return
Figure 9.2 TXINT Interrupt Processing Routine (using HD64180)
9.1.3 Reception by Programmed I/O (Bi-Sync Mode)
Initialization: An example of an initialization program is given below.
CMD fl 21H........................................ Resets channel.
MD0 fl 44H........................................ Specifies bi-sync mode.
Disables the auto-enable function.
Specifies CRC-16 mode, and presets to all 0s.
MD2 fl 00H........................................ Specifies the NRZ code.
Specifies full-duplex mode.
CTL fl 05H........................................ Specifies SYN character load.
RRC fl 00H........................................ RXRDY = 1 when the receive buffer is not empty.
RXS fl 00H........................................ Specifies RXC line input for the receive clock.
IE0 fl 41H........................................ Enables RXINT interrupts.
Enables RXRDY interrupts.
Rev. 0, 07/98, page 330 of 453