CHAPTER 22 INTERRUPT FUNCTIONS
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User’s Manual U12697EJ3V0UM
Figure 22-24. Type A Macro Service Channel
(a) 1-byte transfers
7
0
Macro service counter (MSC)
SFR pointer (SFRP)
Macro service buffer 1
Macro service buffer 2
Macro service buffer n
Channel pointer
Mode register
Macro service
control word
Macro service
channel
Higher addresses
Lower addresses
Macro service buffer address = (channel pointer) – (macro service counter) – 1
MSC = 1
MSC = 2
MSC = n
(b) 2-byte transfers
7
0
Macro service counter (MSC)
SFR pointer (SFRP)
Macro service
buffer 1
Macro service
buffer 2
Macro service
buffer n
Channel pointer
Mode register
Macro service
control word
Macro service
channel
Higher addresses
Lower addresses
Macro service buffer address = (channel pointer) – (macro service counter)
×
2 – 1
MSC = 1
MSC = 2
MSC = n
(Higher byte)
(Lower byte)
(Higher byte)
(Lower byte)
(Higher byte)
(Lower byte)