CP2120-GM Silicon Laboratories Inc, CP2120-GM Datasheet - Page 11

• Manufacturer Part Number: CP2120-GM
• Description: IC I/O EXPANDER I2C/SPI 8B 20QFN
• Manufacturer: Silicon Laboratories Inc
• Type: SPI to I2C Bridger

Specifications of CP2120-GM

• Package / Case: 20-QFN
• Interface: I²C, SPI
• Number Of I /o: 8
• Interrupt Output: Yes
• Frequency - Clock: 400kHz
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 55 C
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: 336-1324

5.2.2. Read From Internal Register
A Read from Internal Register command retrieves the current value of one of the CP2120's internal registers. The
command begins with the command byte, 0x21, followed by the internal register address. This byte is followed by
the transmission of a "don't care" byte, which can be of any value and is ignored by the CP2120. After the "don't
care" byte, the internal register value is transmitted across the MISO line.
5.3. SPI Byte Orientation
The SPI Configuration command configures the bit orientation of transfers across the SPI bus to one of two states.
If SPI transmits most-significant-bit first, bit 7 is transmitted first. If SPI transmits least-significant-bit first, bit 0 is
transmitted first.
5.3.1. SPI Configuration
The command begins with the command byte (0x18), followed by SPI Configuration byte, which should equal one
of the values shown in the following table. Any values other than those listed in the table are ignored.
5.4. SPI Timing Diagrams
SCK*
MISO
MOSI
T
NSS
SEZ
SPI Master
CP2120
T
SE
SPI Master
COMMAND
T
CKH
T
0x21
SOH
T
Byte Value
SIS
0x81
0x42
COMMAND
Figure 4. SPI Slave Timing
T
CKL
0x18
T
REGISTER
SIH
Address
Rev. 0.4
Least Significant Bit First
Most Significant Bit First
Configuration
CONFIGURATION
Don’t Care
SPI
T
REGISTER
SLH
DATA
T
SD
CP2120
T
SDZ
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