SNIU028D February 2016 – September 2020 UCD3138 , UCD3138064 , UCD3138064A , UCD3138128 , UCD3138A , UCD3138A64
Address FFFFFFD0
The clock control Register configures the MCLK divider for low power modes and the clock multiplexer which drives the Sync pin when configured to output the CLKOUT signal. CLKCNTRL is accessible in user and privilege mode and supports byte, half-word and word accesses. Any access to this Register takes two SYSCLK cycles.
9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 0 |
M_DIV_RATIO | Reserved | CLKSR | Reserved | CLKDOUT | Reserved |
R-00 | R-0 | R/W-00 | R-0 | R/W-0 | R-000 |
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset |
Bit | Field | Type | Reset | Description |
---|---|---|---|---|
9-8 | M_DIV_RATIO | R | 00 | MCLK (Processor Clock) Divide Ratio 00 = MCLK frequency equals High Frequency Oscillator divided by 8 (Default) 01 = MCLK frequency equals High Frequency Oscillator divided by 16 10 = MCLK frequency equals High Frequency Oscillator divided by 32 11 = MCLK frequency equals High Frequency Oscillator divided by 64 |
7 | Reserved | R | 0 | |
6-5 | CLKSR | R/W | 00 | These bits control the source/function of CLKOUT 00 = Driven by value in CLKDOUT (Bit 3) (Default) 01 = Driven by the interface clock (ICLK) 10 = Driven by the CPU clock (MCLK) 11 = Driven by the system clock (SYSCLK) |
4 | Reserved | R | 0 | |
3 | CLKDOUT | R/W | 0 | This pin represents the output value of CLKOUT 0 = CLKOUT driven to logic low in output mode (Default) 1 = CLKOUT driven to logic high in output mode |
2-0 | Reserved | R | 000 |