mc56f801 Freescale Semiconductor, Inc, mc56f801 Datasheet - Page 76

• Manufacturer Part Number: mc56f801
• Description: 16-bit Digital Signal Controllers
• Manufacturer: Freescale Semiconductor, Inc

6.3.10.3
This field represents the lower 16 address bits of the “hard coded” I/O short address.
6.4 Clock Generation Overview
The SIM uses master clocks from the OCCS module to produce the peripheral and system (core and
memory) clocks. The HS_PERF clock input from OCCS operates at three times the system and peripheral
bus rate, or a maximum of 96MHz. The SYS_CLK_x2 clock input from OCCS operates at two times the
system and peripheral bus rate, or a maximum of 64MHz. Peripheral and system clocks are generated at a
maximum of 32MHz by dividing the SYS_CLK_x2 clock by two and gating it with appropriate power
mode and clock gating controls. The PWM and TIMER peripheral clocks can optionally be generated at
three times the normal rate at a maximum 96MHz. These clocks are generated by gating the HS_PERF
clock with appropriate power mode and clock gating controls.
The OCCS configuration controls the operating frequency of the SIM’s master clocks. In the OCCS, either
an external clock or the relaxation oscillator can be selected as the master clock source (MSTR_OSC).
When selected, the relaxation oscillator can be operated at full speed (8MHz), standby speed (400kHz
using ROSB), or powered down (using ROPD). An 8MHz MSTR_OSC can be multiplied to 196MHz
using the PLL and postscaled to provide a variety of high speed clock rates. Either the postscaled PLL
output or MSTR_OSC signal can be selected to produce the master clocks to the SIM. When the PLL is
not selected, the HS_PERF clock is disabled and the SYS_CLK_x2 clock is MSTR_OSC.
In combination with the OCCS module, the SIM provides power modes (see
(SIM_PCE register, CLK_DIS, ONCE_EBL), and clock rate controls (TCR, PCR) to provide flexible
control of clocking and power utilization. The SIM’s clock enable controls can be used to disable
individual clocks when not needed. The clock rate controls enable the high speed clocking option for the
Timer channels and PWM but require the PLL to be on and selected. Refer to the 56F801X Peripheral
Reference Manual for further details.
6.5 Power-Down Modes
The 56F8014 operates in one of five Power-Down modes, as shown in
76
Base + $E
RESET
Write
Read
Figure 6-14 I/O Short Address Location Low Register (SIM_IOSALO)
Input/Output Short Address Location (ISAL[21:6])—Bit 15–0
15
1
14
1
13
1
12
1
11
56F8014 Technical Data, Rev. 9
1
10
1
9
1
8
1
ISAL[21:6]
7
1
6
1
5
1
Table 6-3
4
1
Section
.
3
1
Freescale Semiconductor
6.5), clock enables
2
1
1
1
Preliminary
0
1