Enhanced Modular I/O Subsystem (eMIOS200)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
Freescale Semiconductor
26-27
Preliminary
Figure 26-23. Modulus Counter Buffered (MCB) Up/Down Mode
describes the A1 register update process in up counter mode. The A1 load signal is generated
based on the detection of the internal counter reaching one and has the duration of one system clock cycle.
During the load pulse A1 still holds its previous value. It is updated at the second system clock cycle only.
Figure 26-24. MCB Mode A1 Register Update in Up Counter Mode
describes the A1 register update in up/down counter mode. Note that A2 can be written at
any time within cycle (n) in order to be used in cycle (n+1). Thus A1 receives this new value at the next
cycle boundary. The update disable bits OUDIS[n] can be used to disable the update of A1 register.
EMIOS_CCNTR[n]
Time
Write to A2
Match A1
Match A1
Write to A2
0x000001
0x000005
0x000006
0x000007
FLAG Set Event
0x000005
0x000007
A2 Value
A1 Value
0x000006
0x000005
0x000007
A1 Value
0x000008
0x000008
0x000001
Internal Counter
0x000004
0x000006
A2 Value
0x000008
0x000004
0x000006
0x000002
0x000004
0x000006
Write to A2
A1 Load Signal
8
4
6
Counter = A1
Time
Cycle n
Cycle n+1
Cycle n+2
Match A1
Match A1
Match A1
Write to A2
1