<ꢀ5ꢁꢀꢂꢃ<ꢀ.ꢁꢀꢂ
'PJCPEGFꢄ<ꢁꢀꢂꢄ/KETQRTQEGUUQT
ZiLOG
6+/'4ꢄ%10641.ꢄ4')+56'4
The Timer Control Register (6%4) monitors both channels
(246ꢀꢇꢅ246ꢄ) 6/&4 status. It also controls the enabling
anddisablingofdown-countingandinterrupts, andcontrols
the output pin #ꢄꢆꢌ6
for 246ꢄ.
ꢍ
$KV
ꢊ
ꢁ
ꢏ
ꢎ
ꢂ
ꢄ
ꢀ
6+(ꢀ
4
6+'ꢄ
4ꢌ9
6+'ꢀ
4ꢌ9
61%ꢄ
4ꢌ9
61%ꢀ
4ꢌ9
6&'ꢄ
4ꢌ9
6&'ꢀ
4ꢌ9
ꢅ6+(ꢄ
4
(KIWTG ꢉꢈꢆ 6KOGTꢄ%QPVTQNꢄ4GIKUVGTꢄꢌ6%4ꢅꢄ+ꢃ1ꢄ#FFTGUUꢄꢒꢄꢁꢂ*ꢍ
6+(ꢁꢅꢄ6KOGTꢄ+PVGTTWRVꢄ(NCIꢄꢁꢄꢌ$KVꢄꢐꢍꢄꢆꢄWhen 6/&4ꢄ dec-
rements toꢅ0, 6+(ꢄ is set to 1. This condition generates an
interrupt request if enabled by 6+'ꢄꢅꢐ 1. 6+(ꢄ is reset toꢅ0
when 6%4 is read and the higher or lower byte of 6/&4ꢄ
is read. During 4'5'6, 6+(ꢄ is cleared to 0.
61%ꢄ and 61%ꢀ, the #ꢄꢆꢌ6
Low, or toggled when 6/&4ꢄ decrements to 0.
pin can be forced High,
6CDNG ꢁꢇꢆ 6KOGTꢄ1WVRWVꢄ%QPVTQN
61%ꢁ 61%ꢂ
1WVRWV
6+(ꢂꢅꢄ6KOGTꢄ+PVGTTWRVꢄ(NCIꢄꢂꢄꢌ$KVꢄꢈꢍꢆꢄWhen 6/&4ꢀ dec-
rements toꢅ0, 6+(ꢀ is set to 1. This condition generates an
interrupt request if enabled by 6+'ꢀꢅꢐ 1. 6+(ꢀ is reset toꢅ0
when 6%4 is read and the higher or lower byte of 6/&4ꢀ
is read. During 4'5'6, 6+(ꢀ is cleared to 0.
ꢀ
ꢀ
+PJKDKVGF 6JGꢅ#ꢄꢆꢌ6
ꢅRKPꢅKUꢅPQVꢅ
CHHGEVGFꢅD[ꢅVJGꢅ246
ꢀ
ꢄ
ꢄ
ꢄ
ꢀ
ꢄ
6QIINGF +HꢅDKVꢅꢍꢅQHꢅ+#4ꢄ$ꢅKUꢅꢄꢇꢅVJGꢅ
#ꢄꢆꢌ6
ꢅRKPꢅKUꢅVQIINGFꢅQTꢅ
ꢀ
ꢄ
UGVꢅ.QYꢅQTꢅ*KIJꢅCUꢅ
KPFKECVGF
6+'ꢁꢅꢄ6KOGTꢄ+PVGTTWRVꢄ'PCDNGꢄꢁꢄꢌ$KVꢄꢑꢍꢆꢄWhen 6+'ꢀ is set
to 1, 6+(ꢄꢅꢐ 1 generates a CPU interrupt request. When
6+'ꢀ is reset toꢅ0, the interrupt request is inhibited. During
4'5'6, 6+'ꢀ is cleared to 0.
6&'ꢁꢎꢄꢂꢅꢄ6KOGTꢄ&QYPꢄ%QWPVꢄ'PCDNGꢄꢌ$KVUꢄꢁꢎꢄꢂꢍꢆꢄ6&'ꢄ
and 6&'ꢀ enable and disable down-counting for 6/&4ꢄ
and 6/&4ꢀ, respectively. When 6&'P (Pꢅꢐ ꢀ,ꢄ) is set to
1, down-counting is stopped and 6/&4P is freely read or
written. 6&'ꢄ and 6&'ꢀ are cleared toꢅ0during 4'5'6 and
6/&4P does not decrement until 6&'P is set to ꢄ.
61%ꢁꢎꢄꢂꢅꢄ6KOGTꢄ1WVRWVꢄ%QPVTQNꢄꢌ$KVUꢄꢋꢎꢄꢇꢍꢆꢄ61%ꢄ and
61%ꢀ control the output of 246ꢄ using the multiplexed
#ꢄꢆꢌ6
pin as indicated in Table 12. During 4'5'6,
61%ꢄ and 61%ꢀ are cleared to 0. If bit 3 of the +#4ꢄ$ reg-
ister is 1, the 6
function is selected. By programming
ꢎꢆ
2ꢅ4ꢅ'ꢅ.ꢅ+ꢅ/ꢅ+ꢅ0ꢅ#ꢅ4ꢅ;
&5ꢀꢀꢁꢀꢀꢂꢃ</2ꢀꢂꢀꢀ
ZILOG [ ZILOG, INC. ]
