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Enhanced Modular Input/Output Subsystem (eMIOS200)
PXN20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor
28-37
Figure 28-33. Modulus Counter Up Mode Example
Figure 28-34. Modulus Counter Up/Down Mode Example
28.4.1.1.11
Modulus Counter Buffered (MCB) Mode
The MCB mode provides a time base that can be shared with other channels through the internal counter
buses. Register A1 is double buffered, thus allowing smooth transitions between cycles when changing A2
register value. Register A1 is updated at the cycle boundary, which is defined as when the internal counter
reaches the value one. The internal counter values are within a range from 0x00_0001 to the value of
register A1 in MCB mode. The internal counter must not reach 0x00_0000 as a consequence of a
rollover.To avoid this, the user must start MCB only if the value stored in the internal counter is less than
the value stored in the EMIOS_CADR[
n
] register.
MODE[6] bit selects the internal clock source if set to 0 or external, if set to 1. When the external clock is
selected the input channel pin is used as the channel clock source. The active edge of this clock is defined
by EDPOL and EDSEL bits in the EMIOS_CCR channel register.
When entering in MCB mode, if the up counter is selected by MODE[4] = 0, the internal counter starts
counting from its current value to up direction until A1 match occurs. On the next system clock cycle after
the A1 match occurs, the internal counter is set to one. If up/down counter is selected by setting
0xFFFFFF
0x000303
0x000000
EMIOS_CCNTR[n]
Time
A1 Match
A1 Value
1
0x000303
0x000303
0x000200
Write to A2
A1 Match
Write to A2
0x000200
A1 Match
A1 Match
0xxxxxxx
FLAG Pin/Register
Notes: 1. EMIOS_CADR[n] = A1
0x000303
0x000200
A2 = A1 according to OU[n] bit
MODE[4] = 0
0xFFFFFF
0x000303
0x000000
EMIOS_CCNTR[n]
Time
A1 Match
A1 Value
1
0x000303
0x000303
0x000200
Write to A2
B1 Match (=0)
Write to A2
0x000200
A1 Match
B1 Match (=0)
0xxxxxxx
Notes: 1. EMIOS_CADR[n] = A1
0x000200
0x000200
FLAG Pin/Register
A2 = A1 according to OU[n] bit
MODE[4] = 1
Summary of Contents for PXN2020
Page 1: ...PXN20 Microcontroller Reference Manual Devices Supported PXN2020 PXN2120 PXN20RM Rev 1 06 2011...
Page 42: ...PXN20 Microcontroller Reference Manual Rev 1 lxiv Freescale Semiconductor...
Page 64: ...Introduction PXN20 Microcontroller Reference Manual Rev 1 1 22 Freescale Semiconductor...
Page 112: ...Signal Description PXN20 Microcontroller Reference Manual Rev 1 3 44 Freescale Semiconductor...
Page 118: ...Resets PXN20 Microcontroller Reference Manual Rev 1 4 6 Freescale Semiconductor...
Page 372: ...e200z6 Core Z6 PXN20 Microcontroller Reference Manual Rev 1 13 8 Freescale Semiconductor...
Page 412: ...e200z0 Core Z0 PXN20 Microcontroller Reference Manual Rev 1 14 14 Freescale Semiconductor...
Page 821: ...Media Local Bus MLB PXN20 Microcontroller Reference Manual Rev 1 Freescale Semiconductor 27 49...
Page 822: ...Media Local Bus MLB PXN20 Microcontroller Reference Manual Rev 1 27 50 Freescale Semiconductor...
Page 1376: ...Memory Map PXN20 Microcontroller Reference Manual Rev 1 A 118 Freescale Semiconductor...