Freescale Semiconductor MPC8260 - Manual (Page 218)

System Interface Unit (SIU)
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
4-46 Freescale Semiconductor
4.3.3 Periodic Interrupt Registers
The periodic interrupt registers are described in the following sections.
4.3.3.1 Periodic Interrupt Status and Control Register (PISCR)
The periodic interrupt status and control register (PISCR), shown in Figure 4-38 , contains the interrupt
request level and the interrupt status bit. It also contains the controls for the 16 bits to be loaded in a
modulus counter.
Table 4-21 describes PISCR fields.
4.3.3.2 Periodic Interrupt Timer Count Register (PITC)
The periodic interrupt timer count register (PITC), shown in Figure 4-39 , contains the 16 bits to be loaded
in a modulus counter.
0 7 8 9 12 13 14 15
Field — PS — PIE PTF PTE
Reset 0000_0000_0000_0000
R/W R/W
Addr 0x0x10240
Figure 4-38. Periodic Interrupt Status and Control Register (PISCR)
Table 4-21. PISCR Field Descriptions
Bits Name Description
0–7 — Reserved, should be cleared.
8 PS Periodic interrupt status. Asserted if the PIT issues an interrupt. The PIT issues an interrupt after the
modulus counter counts to zero. The PS bit can be negated by writing a one to PS. A write of zero has
no effect on this bit.
9–12 — Reserved, should be cleared.
13 PIE Periodic interrupt enable. If PIE = 1, the periodic interrupt timer generates an interrupt when PS = 1.
14 PTF Periodic interrupt frequency. The input clock to the periodic interrupt timer may be either 4 MHz or
32 KHz. The user should set the PTF bit according to the frequency of this clock.
0 The input clock to the periodic interrupt timer is 4 MHz.
1 The input clock to the periodic interrupt timer is 32 KHz.
See
Section 4.1.2, “Timers Clock,” for further details
15 PTE Periodic timer enable. This bit controls the counting of the periodic interrupt timer. When the timer is
disabled, it maintains its old value. When the counter is enabled, it continues counting using the
previous value.
0 Disable counter.
1 Enable counter