COP8AME9_14 Datasheet, PDF (60/102 Pages) Texas Instruments – COP8AME9 8-Bit CMOS Flash Microcontroller with 8k Memory, Dual Op Amps, Virtual EEPROM, Temperature Sensor, 10-Bit A/D and Brownout Reset

COP8AME9, COP8ANE9
SNOS930F – MARCH 2001 – REVISED MARCH 2013
www.ti.com
Channel Select
This 4-bit field selects one of seven channels to be the V_IN+. The mode selection and the mux output determine
the V_IN-input. When MUX = 0, all seven channels are available, as shown in Table 24. When MUX = 1, only 4
channels are available, as shown in Table 25.
Table 24. A/D Converter Channel Selection when the Multiplexor Output is Disabled
ADCH3
0
1
1
1
1
1
1
Select Bits
ADCH2
1
0
0
1
1
1
1
ADCH1
1
1
1
0
0
1
1
ADCH0
1
0
1
0
1
0
1
Mode Select
ADMOD = 0
Single Ended
Mode
Channel No.
Temp sensor, if
enabled
10
11
12
13
14
15
Mode Select
ADMOD = 1
Differential Mode
Channel Pairs (+, −)
Not used
10, 11 ⁽¹⁾
11, 10 ⁽¹⁾
12, 13 ⁽¹⁾
13, 12 ⁽¹⁾
14, 15 ⁽¹⁾
15, 14 ⁽¹⁾
Mux Output
Disabled
MUX
0
0
0
0
0
0
0
(1) Only if the programmable gain amplifier is bypassed.
Multiplexor Output Select
The MUX bit field allows the output of the A/D multiplexor (with the exception of the temperature sensor channel)
and the input to the A/D to be connected directly to external pins. This allows for an external, common
filter/signal conditioning circuit to be applied to all channels. The output of the external conditioning circuit can
then be connected directly to the input of the Sample and Hold input on the A/D Converter. See Figure 28 for the
single ended mode diagram. The Multiplexor output is connected to ADCH4 and the A/D input is connected to
ADCH5. For differential mode, the differential multiplexor outputs are available and should be converted to a
single ended voltage for connection to the A/D Converter Input. The programmable gain amplifier must be
bypassed when using the multiplexor output feature in differential mode. See Figure 29.
The channel assignments for this mode are shown in Table 25.
When using the Mux Output feature, the delay though the internal multiplexor to the pin, plus the delay of the
external filter circuit, plus the internal delay to the Sample and Hold will exceed the three clock cycles that's
allowed in the conversion. This requires that whenever the MUX bit = 1, that the channel selected by ADCH3:0
bits, be enabled, even when ADBSY = 0, and gated to the mux output pin. The input path to the A/D converter
should also be enabled. This allows the input channel to be selected and settled before starting a conversion.
The sequence to perform conversions using the Mux Out feature is a multistep process and is listed below.
1. Select the desired channel, excluding the temperature sensor channel, and operating modes and load them
into ENAD without setting ADBSY.
2. Wait the appropriate time until the analog input has settled. This will depend on the application and the
response of the external circuit.
3. Select the same desired channel and operating modes used in step 1 and load them into ENAD and also set
ADBSY. This will start the conversion.
4. After conversion is completed, obtain the results from the result registers.
60
Submit Documentation Feedback
Copyright © 2001–2013, Texas Instruments Incorporated
Product Folder Links: COP8AME9 COP8ANE9