TMS370CX9X_05 Datasheet, PDF (28/55 Pages) Texas Instruments – 8-BIT MICROCONTROLLER

TMS370Cx9x
8-BIT MICROCONTROLLER
SPNS036B – JANUARY 1996 – REVISED FEBRUARY 1997
analog-to-digital converter 3 module (continued)
Table 15. ADC3 Peripheral Control Register (ADCTL)
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{Bit #}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _P070
7
CONVERT
START
R W– 0
6
SAMPLE
START
RW – 0
5
REF VOLT
SELECT1
RW – 0
4
REF VOLT
SELECT0
RW – 0
3
AD INPUT
SELECT3
RW – 0
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{R = read, W = write, –n = value of the bit after the register is reset}
2
AD INPUT
SELECT2
RW – 0
1
AD INPUT
SELECT1
RW – 0
0
AD INPUT
SELECT0
RW – 0
BIT 0–3 AD INPUT SELECT 0–3 (Analog Input Channel Select Bits 0 – 3)
These bits select the channel used for conversion. Channels should be changed only after the
ADC3 has cleared the SAMPLE START and CONVERT START bits. Changing the channel while
either SAMPLE START or CONVERT START is 1 invalidates the conversion in progress.
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{AD INPUT}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{SELECT 3}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₀
0
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₀
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₀
0
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₀
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₀
0
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₁
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 1
1
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₁
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 1
1
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₁
AD INPUT
SELECT 2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
AD INPUT
SELECT 1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
AD INPUT
SELECT 0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
AD INPUT
CHANNEL
AN0
AN1
AN2
AN3
AN4
AN5
AN6
AN7
AN8
AN9
AN10
AN11
AN12
AN13
AN14
BIT 4–5
REF VOLT SELECT 4–5 (Reference Voltage (+V_REF) Select Bits 4–5)
These bits select the channel the ADC3 uses for the positive voltage reference. These bits must
BIT 6
not change during the entire conversion.
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ REF VOLT
SELECT 1
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₀
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₀
1
REF VOLT
SELECT 0
0
1
0
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{SAMPLE START (Sample Start)}
+VREF
SOURCE
VCC3
AN6
AN7
Setting this bit stops any ongoing conversion and starts sampling the selected input channel to
begin a new conversion. This bit is cleared by the ADC3. Entering HALT or STANDBY mode clears
this bit and aborts any sampling in progress.
BIT 7
CONVERT START (Conversion Start)
Setting this bit starts the conversion. This bit is cleared by the ADC3. Entering HALT or STANDBY
mode clears this bit and aborts any conversion in progress.
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