dsp56800eerm Freescale Semiconductor, Inc, dsp56800eerm Datasheet - Page 115

• Manufacturer Part Number: dsp56800eerm
• Description: 16-bit Digital Signal Controllers
• Manufacturer: Freescale Semiconductor, Inc

6.5.7.7
Selects clock to be muxed out on the CLKO pin.
6.5.8
The GPIO Peripheral Select register can be used to multiplex out any one of the three alternate peripherals
for GPIOC. The default peripheral is Quad Decoder 1 and Quad Timer B (NOT available in the 56F8157
device); these peripherals work together.
The four I/O pins associated with GPIOC can function as GPIO, Quad Decoder 1/Quad Timer B, or as
SPI 1 signals. GPIO is not the default and is enabled/disabled via the GPIOC_PER, as shown in
Figure 6-10
choice between decoder/timer and SPI inputs/outputs is made in the SIM_GPS register and in conjunction
with the Quad Timer Status and Control Registers (SCR). The default state is for the peripheral function
of GPIOC[3:0] to be programmed as decoder functions. This can be changed by altering the appropriate
controls in the indicated registers.
Freescale Semiconductor
Preliminary
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00000 = SYS_CLK (from OCCS - DEFAULT)
00001 = Reserved for factory test—56800E clock
00010 = Reserved for factory test—XRAM clock
00011 = Reserved for factory test—PFLASH odd clock
00100 = Reserved for factory test—PFLASH even clock
00101 = Reserved for factory test—BFLASH clock
00110 = Reserved for factory test—DFLASH clock
00111 = Oscillator output
01000 = F
01001 = Reserved for factory test—IPB clock
01010 = Reserved for factory test—Feedback (from OCCS, this is path to PLL)
01011 = Reserved for factory test—Prescaler clock (from OCCS)
01100 = Reserved for factory test—Postscaler clock (from OCCS)
01101 = Reserved for factory test—SYS_CLK2 (from OCCS)
01110 = Reserved for factory test—SYS_CLK_DIV2
01111 = Reserved for factory test—SYS_CLK_D
10000 = ADCA clock
10001 = ADCB clock
GPIO Peripheral Select Register (SIM_GPS)
CLockout Select (CLKOSEL)—Bits 4–0
and
out
Table
(from OCCS)
6-2. When GPIOC[3:0] are programmed to operate as peripheral I/O, then the
56F8357 Technical Data, Rev. 15
Register Descriptions
115