DEMO9S12XEP100 Freescale Semiconductor, DEMO9S12XEP100 Datasheet - Page 690

• Manufacturer Part Number: DEMO9S12XEP100
• Description: BOARD DEMO FOR MC9S12XEP100
• Manufacturer: Freescale Semiconductor
• Type: MCUr

Specifications of DEMO9S12XEP100

• Contents: Board, Cables, CD
• Processor To Be Evaluated: MC9S12XEP100
• Data Bus Width: 16 bit
• Interface Type: RS-232
• Silicon Manufacturer: Freescale
• Core Architecture: S12
• Core Sub-architecture: S12
• Silicon Core Number: MC9S12
• Silicon Family Name: S12XE
• Rohs Compliant: Yes
• For Use With/related Products: MC9S12XEP100
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Chapter 18 Periodic Interrupt Timer (S12PIT24B4CV2)
Whenever the micro timer down-counter has counted to zero the PITMTLD register is reloaded and the
connected 16-bit modulus down-counters count one cycle.
Whenever a 16-bit timer counter and the connected 8-bit micro timer counter have counted to zero, the
PITLD register is reloaded and the corresponding time-out flag PTF in the PIT time-out flag (PITTF)
register is set, as shown in
micro timer load (PITMTLD) registers and the bus clock f
For example, for a 40 MHz bus clock, the maximum time-out period equals:
The current 16-bit modulus down-counter value can be read via the PITCNT register. The micro timer
down-counter values cannot be read.
The 8-bit micro timers can individually be restarted by writing a one to the corresponding force load micro
timer PFLMT bits in the PIT control and force load micro timer (PITCFLMT) register. The 16-bit timers
can individually be restarted by writing a one to the corresponding force load timer PFLT bits in the PIT
forceload timer (PITFLT) register. If desired, any group of timers and micro timers can be restarted at the
same time by using one 16-bit write to the adjacent PITCFLMT and PITFLT registers with the relevant
bits set, as shown in
690
Because of an order from the United States International Trade Commission, BGA-packaged product lines and partnumbers
Note 1. The PTF flag clearing depends on the software
16-Bit Force Load
indicated here currently are not available from Freescale for import or sale in the United States prior to September 2010
PITCNT Register
8-Bit Force Load
Timer Counter
time-out period = (PITMTLD + 1) * (PITLD + 1) / f
256 * 65536 * 25 ns = 419.43 ms.
8-Bit Micro
PTF Flag
Bus Clock
PITTRIG
1
Figure
00
0
2
Figure
18-20.
0001
Time-Out Period
Figure 18-20. PIT Trigger and Flag Signal Timing
1
MC9S12XE-Family Reference Manual , Rev. 1.23
0
18-20. The time-out period is a function of the timer load (PITLD) and
2
0000
1
0
2
0001
1
0
BUS
2
0000
BUS
:
1
.
2
Time-Out Period
0001
1
After Restart
0
2
0000
1
Freescale Semiconductor
0
2
0001
1
0
2