HP 271308 Technical Reference Manual page 49

HP 27130B
Table 3-7. eTC Timer Outputs
TIMER DRIVEN DEVICE
CTC CTC
OUTPUT INPUT
NO.
CH. MNEMONIC MNEMONIC FUNCTION
0
0
IRQH
IRQH of MIC Reguest hold-off for DMA
0
1 BRG1 SID 0 MUX card channel 1 baud-
RXCB- & TXCB- rate clock
0 2
BRGO SID 0 MUX card channel
o
baud-
RXCA-
&
TXCA- rate clock
0
3
INTERNAL Cause zero Real-time clock for
count interrupt firmNare
to Z-80B CPU
1
0
BRG2 SID 1 MUX card channel 2 baud-
RXCA- & TXCA- rate clock
1 1 BRG3 SID 1 MUX card channel 3 baud-
RXCB-
&
TXCB-
rate clock
1
2
BRG4 SID 2 MUX card channel 4 baud-
RXCA-
&
TXCA- rate clock
1
3
Not available Counter value can be
read (polled) by Z-80B
CPU
3-21