Clock Generation and Reset Control Registers
15-70
Table 15–23. DSP System Status Register (DSP_SYSST) – Offset Address: 0x18
(Continued)
Bit
Reset
Value
Type
Description
Value
Name
1
GLOB_SWRST
This read/clear-only status bit indicates whether or not
reset has been asserted due to a global software
reset. This bit is cleared to logic 0 upon an external
reset pulse asserting at CHIP_nRESET signal, or by
writing it to logic 0. This bit cannot be written to logic
1 from TIPB interface. See Note 2.
R/C
0
0
A global software reset has not been requested.
1
A global software reset has been requested.
0
DSP_WDRST
This read/clear-only status bit indicates whether or not
reset has been asserted due to a DSP timer/watchdog
underflow. This bit is cleared to logic 0 upon an
external reset pulse at CHIP_nRESET signal or by
writing it to logic 0. This bit cannot be written to logic
1 from peripheral bus interface.
R/C
0
0
DSP timer/watchdog underflow has not occurred.
1
DSP timer/watchdog underflow has generated reset.
Notes:
1) This bit is only to be used for test/debug purposes only.
2) In the OMAP5910 device, the DSP_EN and ARM_RST bits (located in ARM_RSTCT1) must be set together to
activate the global software reset. Setting the SW_RST bit only (DSP_RSTCT1) results in global software reset
flag.
15.4.1 DPLL Operation Mode Registers
The digital phase-locked loop (DPLL) can be operated either in bypass mode,
in lock mode, or in idle mode.
-
In lock mode, the DPLL synthesizes a frequency clock (CLKOUT) from a
fixed reference clock signal (CLKREF). The output frequency is an integer
multiple or fractional multiple (m/n, respectively PLL_MULT and PLL_DIV
bit field) of the input reference. With 1 < m < 31 and 1 < n < 4, the frequency
output ranges from CLKREF /4 to 31x CLKREF.
-
In bypass mode, the DPLL output clock in bypass mode can be CLKREF
(input clock), CLKREF/2, or CLKREF/4 depending on the BYPASS_DIV
bit field value.
-
In idle mode, the DPLL circuitry is disabled. The output clock is held in a
high static level and the configuration data is maintained.