MCP3201 Microchip Technology, MCP3201 Datasheet - Page 14

• Manufacturer Part Number: MCP3201
• Description: 2.7V 12-Bit A/D Converter with SPI Serial Interface
• Manufacturer: Microchip Technology

MCP3201
5.0
Communication with the device is done using a stan-
dard SPI-compatible serial interface. Initiating commu-
nication with the MCP3201 begins with the CS going
low. If the device was powered up with the CS pin low,
it must be brought high and back low to initiate commu-
nication. The device will begin to sample the analog
input on the first rising edge after CS goes low. The
sample period will end in the falling edge of the second
clock, at which time the device will output a low null bit.
The next 12 clocks will output the result of the conver-
FIGURE 5-1:
FIGURE 5-2:
DS21290B-page 14
D
D
CLK
CS
OUT
CLK
CS
OUT
* After completing the data transfer, if further clocks are applied with CS low, the A/D Converter will output LSB first data, followed
** t
t
SERIAL COMMUNICATIONS
by zeros indefinitely. See Figure below.
SAMPLE
node, leaving the CLK running to clock out the LSB-first data or zeros.
DATA
* After completing the data transfer, if further clocks are applied with CS low, the A/D Converter will output zeros indefinitely.
** t
HI-Z
node, leaving the CLK running to clock out the LSB-first data or zeros.
: during this time, the bias current and the comparator power down and the reference input becomes a high impedance
DATA
HI-Z
Communication with MCP3201 using MSB first Format.
Communication with MCP3201 using LSB first Format.
: during this time, the bias current and the comparator power down and the reference input becomes a high impedance
t
SUCS
t
SAMPLE
t
NULL
SUCS
BIT B11 B10
NULL
BIT
B11 B10 B9
B9
B8
t
CONV
B7
B6
B8
B5
t
CYC
B7
t
CONV
B4
Preliminary
B6
B3
B2
B5
B1
t
B4
CYC
B0
B3
sion with MSB first, as shown in Figure 5-1. Data is
always output from the device on the falling edge of the
clock. If all 12 data bits have been transmitted and the
device continues to receive clocks while the CS is held
low, the device will output the conversion result LSB
first, as shown in Figure 5-2. If more clocks are pro-
vided to the device while CS is still low (after the LSB
first data has been transmitted), the device will clock
out zeros indefinitely.
B1
B2
B2
B3
B1 B0
t
CSH
B4
*
B5
t
DATA
t
Power Down
DATA
B6
**
**
Power
Down
HI-Z
B7
B8
1999 Microchip Technology Inc.
B9 B10
NULL
BIT
t
CSH
B11 B10 B9
B11
*
HI-Z
B8