User’s Manual
C166S V1 SubSystem
Central Processing Unit
User’s Manual
3-38
V 1.6, 2001-08
3.4.6.3
Short Transfer Mode
If the short transfer mode is enabled by the PT flag (PT = 0) in the PEC control register
PECCx, the PEC Transfer Count Field (COUNT) of the PECCx controls directly the
action of the respective PEC channel. The contents of the bitfield COUNT may specify
a certain number of PEC transfers, unlimited transfers, or no PEC service at all.
a) If the PEC transfer counter (COUNT) value is set to 00
H
, the normal interrupt
requests are processed instead of PEC data transfers, and the corresponding PEC
channel remains idle.
b) Continuous data transfers are selected by setting the bitfield COUNT to FF
H
. In this
case, COUNT is not decremented by the transfers, and the respective PEC channel
can serve unlimited number of PEC requests until it is modified by the program.
c) If the bitfield COUNT is set to service a specified number of requests by the
respective PEC channel, it is decremented with each PEC transfer, and the request
flag is cleared to indicate that the request has been serviced. When COUNT
reaches 00
H
it activates the ISR that has the same priority level (EOPINT = 0), or
triggers the EOP ISR with a different priority level (EOPINT = 1). When COUNT is
decremented from 01
H
to 00
H
after a data transfer, the request flag will be cleared
if EOPINT is set to 1. If EOPINT is 0, the request flag will not be cleared and another
interrupt request will be generated on the same priority level. The respective PEC
channel remains idle, and the associated ISR is activated instead of PEC transfer,
because COUNT contains the 00
H
value.
Содержание C166S V1 SubSystem
Страница 10: ...User s Manual C166S V1 SubSystem User s Manual I 6 V 1 6 2001 08...
Страница 16: ...User s Manual C166S V1 SubSystem Introduction User s Manual 1 6 V 1 6 2001 08...
Страница 126: ...User s Manual C166S V1 SubSystem Central Processing Unit User s Manual 3 96 V 1 6 2001 08...
Страница 178: ...User s Manual C166S V1 SubSystem Memory Organization User s Manual 4 52 V 1 6 2001 08...
Страница 206: ...User s Manual C166S V1 SubSystem Instruction Set User s Manual 5 28 V 1 6 2001 08...
Страница 306: ...User s Manual C166S V1 SubSystem Detailed Instruction Set User s Manual 6 100 V 1 6 2001 08...
Страница 362: ...User s Manual C166S V1 SubSystem The External Bus Interface User s Manual 8 40 V 1 6 2001 08...
Страница 452: ...User s Manual C166S V1 SubSystem General Purpose Timer Unit User s Manual 12 44 V 1 6 2001 08...
Страница 454: ...User s Manual C166S V1 SubSystem Instruction Index User s Manual 13 2 V 1 6 2001 08...
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