MCP3008-I/SL Microchip Technology, MCP3008-I/SL Datasheet - Page 21

• Manufacturer Part Number: MCP3008-I/SL
• Description: IC ADC 10BIT 2.7V 8CH SPI 16SOIC
• Manufacturer: Microchip Technology

Specifications of MCP3008-I/SL

• Number Of Converters: 1
• Package / Case: 16-SOIC (0.154", 3.90mm Width)
• Number Of Bits: 10
• Sampling Rate (per Second): 200k
• Data Interface: Serial, SPI™
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Architecture: SAR
• Conversion Rate: 200 KSPs
• Resolution: 10 bit
• Input Type: Voltage
• Snr: 200 dB
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Package: 16SOIC N
• Sampling Rate: 200 KSPS
• Number Of Adcs: 1
• Number Of Analog Inputs: 8|4
• Digital Interface Type: Serial (4-Wire, SPI)
• Polarity Of Input Voltage: Unipolar
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

6.0
6.1
With most microcontroller SPI ports, it is required to
send groups of eight bits. It is also required that the
microcontroller SPI port be configured to clock out data
on the falling edge of clock and latch data in on the
rising
MCP3004/3008 devices may not need multiples of
eight clocks, it will be necessary to provide more clocks
than are required. This is usually done by sending
‘leading zeros’ before the start bit. As an example,
Figure 6-1
3008 can be interfaced to a MCU with a hardware SPI
port.
Mode 0,0, which requires that the SCLK from the MCU
idles in the ‘low’ state, while
ilar case of SPI Mode 1,1, where the clock idles in the
‘high’ state.
FIGURE 6-1:
(Mode 0,0: SCLK idles low).
© 2008 Microchip Technology Inc.
X = “Don’t Care” Bits
SCLK
D
MCU Received Data
(Aligned with rising
edge of clock)
MCU Transmitted Data
(Aligned with falling
edge of clock)
OUT
D
CS
Figure 6-1
IN
edge.
APPLICATIONS INFORMATION
Using the MCP3004/3008 with
Microcontroller (MCU) SPI Ports
and
converter on rising edges of SCLK
MCU latches data from A/D
Because
Figure 6-2
1
depicts the operation shown in SPI
?
2
0
Data stored into MCU receive
register after transmission of first
8 bits
SPI Communication with the MCP3004/3008 using 8-bit segments
?
3
0
?
communication
shows how the MCP3004/
4
HI-Z
Figure 6-2
0
?
5
0
?
6
Data is clocked out of
A/D converter on falling edges
0
?
7
shows the sim-
0
Start
?
8
0
with
?
Start
SGL/
DIFF
Bit
1
9
the
D2
SGL/
DIFF
?
10
Data stored into MCU receive
register after transmission of
second 8 bits
D1
?
11
D2
DO
?
12 13 14 15 16
D1
As is shown in
the A/D converter contains seven leading zeros before
the start bit. Arranging the leading zeros this way
induces the 10 data bits to fall in positions easily
manipulated by the MCU. The MSB is clocked out of
the A/D converter on the falling edge of clock number
14. Once the second eight clocks have been sent to the
device, the MCU receive buffer will contain five
unknown bits (the output is at high-impedance for the
first two clocks), the null bit and the highest order 2 bits
of the conversion. Once the third byte has been sent to
the device, the receive register will contain the lowest
order eight bits of the conversion results. Employing
this method ensures simpler manipulation of the
converted data.
Figure 6-2
which requires that the clock idles in the high state. As
with mode 0,0, the A/D converter outputs data on the
falling edge of the clock and the MCU latches data from
the A/D converter in on the rising edge of the clock.
?
DO
NULL
BIT B9 B8
?
X
(Null)
0
X
shows the same thing in SPI Mode 1,1,
B9 B8
X
Figure
MCP3004/3008
X
B7
17 18 19
6-1, the first byte transmitted to
B7 B6 B5 B4 B3 B2 B1 B0
B6 B5 B4 B3 B2 B1 B0
Data stored into MCU receive
register after transmission of last
8 bits
Don’t Care
X
X
20 21 22
X
X
DS21295D-page 21
X
23 24
X
X
X