![Freescale Semiconductor ColdFire MCF5211 Скачать руководство пользователя страница 280](http://html1.mh-extra.com/html/freescale-semiconductor/coldfire-mcf5211/coldfire-mcf5211_reference-manual_2330619280.webp)
Programmable Interrupt Timers (PIT0–PIT1)
MCF5213 ColdFire® Integrated Microcontroller Reference Manual, Rev. 3
17-6
Freescale Semiconductor
Figure 17-5. Counter Reloading from the Modulus Latch
17.3.2
Free-Running Timer Operation
This mode of operation is selected when the PCSR
n
[RLD] bit is clear. In this mode, the counter rolls over
from 0x0000 to 0xFFFF without reloading from the modulus latch and continues to decrement.
When the counter reaches a count of 0x0000, PCSR
n
[PIF] flag is set. If the PCSR
n
[PIE] bit is set, PIF flag
issues an interrupt request to the CPU.
When the PCSR
n
[OVW] bit is set, counter can be directly initialized by writing to PMR
n
without having
to wait for the count to reach 0x0000.
Figure 17-6. Counter in Free-Running Mode
17.3.3
Timeout Specifications
The 16-bit PIT counter and prescaler supports different timeout periods. The prescaler divides the internal
bus clock period as selected by the PCSR
n
[PRE] bits. The PMR
n
[PM] bits select the timeout period.
Eqn. 17-1
17.3.4
Interrupt Operation
shows the interrupt request generated by the PIT.
Table 17-6. PIT Interrupt Requests
Interrupt Request
Flag
Enable Bit
Timeout
PIF
PIE
0x0002
0x0001
0x0000
0x0005
0x0005
PIT CLOCK
COUNTER
MODULUS
PIF
0x0002
0x0001
0x0000
0xFFFF
0x0005
PIT CLOCK
COUNTER
MODULUS
PIF
Timeout period
PRE[3:0]
(PM[15:0]
1)
+
×
f
sys 2
⁄
×
=
Содержание ColdFire MCF5211
Страница 48: ...Overview MCF5213 ColdFire Integrated Microcontroller Reference Manual Rev 3 1 14 Freescale Semiconductor...
Страница 158: ...Reset Controller Module MCF5213 ColdFire Integrated Microcontroller Reference Manual Rev 3 9 10 Freescale Semiconductor...
Страница 218: ...Edge Port Module EPORT MCF5213 ColdFire Integrated Microcontroller Reference Manual Rev 3 13 8 Freescale Semiconductor...
Страница 234: ...DMA Controller Module MCF5213 ColdFire Integrated Microcontroller Reference Manual Rev 3 14 16 Freescale Semiconductor...
Страница 378: ...I2 C Interface MCF5213 ColdFire Integrated Microcontroller Reference Manual Rev 3 22 16 Freescale Semiconductor...
Страница 468: ...FlexCAN MCF5213 ColdFire Integrated Microcontroller Reference Manual Rev 3 25 30 Freescale Semiconductor...