Enhanced Modular I/O Subsystem (eMIOS200)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
Freescale Semiconductor
26-23
Preliminary
The input pulse period is calculated by subtracting the value in B1 from A2.
shows how the unified channel can be used for input period measurement.
Figure 26-18. Input Period Measurement Example
describes the A1 and B1 register updates when EMIOS_CADR[n] and EMIOS_CBDR[n]
read operations are performed. When EMIOS_CADR[n] read occurs the content of A1 is transferred to B1
thus providing coherent data in A2 and B1 registers. Transfers from B2 to B1 are then blocked until
EMIOS_CBDR[n] is read. After EMIOS_CBDR[n] is read, register A1 content is transferred to register
B1 and the transfers from B2 to B1 are re-enabled to occur at the transfer edges, which is the leading edge
in the
example.
0x000500
0x001000
0x001100
0x001250
0x001525
0x0016A0
Selected
Counter Bus
FLAG
Set Event
A
A2 (Captured)
Value
2
0xxxxxxx
0x001000
0x001250
0x0016A0
Notes:
1
After input filter
2
EMIOS_CADR[n] = A2
Input Signal
1
EDPOL = 1
A
A
B1 Value
3
0xxxxxxx
0xxxxxxx
0x001000
0x001250
0xxxxxxx
0x001000
0x001250
0x0016A0
B2 (Captured)
Value
3
EMIOS_CBDR[n] = B1
0xxxxxxx
0xxxxxxx
0x001000
0x001250
A1 Value