System and Peripheral Control Registers
155
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
Architecture
Table 2-50. Clock Test Register (CLKTEST) Field Descriptions (continued)
Bit
Field
Value
Description
11-8
SEL_GIO_PIN
GIOB[0] pin clock source valid, clock source select
0
Oscillator valid status
1h
PLL1 valid status
2h-4h
Reserved
5h
High-frequency LPO (Low-Power Oscillator) clock valid status
6h
PLL2 valid status
7h
Reserved
8h
Low-frequency LPO (Low-Power Oscillator) clock valid status
9h-Fh
Reserved
7-4
Reserved
0
Reads return 0. Writes have no effect.
3-0
SEL_ECP_PIN
ECLK pin clock source select
Note: Only valid clock sources can be selected for the ECLK pin. Valid clock
sources are displayed by the CSVSTAT register.
0
Oscillator clock
1h
PLL1 clock output
2h
Reserved
3h
EXTCLKIN1
4h
Low-frequency LPO (Low-Power Oscillator) clock
5h
High-frequency LPO (Low-Power Oscillator) clock
6h
PLL2 clock output
7h
EXTCLKIN2
8h
GCLK
9h
RTI Base
Ah
Reserved
Bh
VCLKA1
Ch
Reserved
Dh
VCLKA3
Eh
VCLKA4
Fh
Reserved
NOTE:
Nonimplemented clock sources should not be enabled or used.