C8051F902-GM Silicon Laboratories Inc, C8051F902-GM Datasheet - Page 256

• Manufacturer Part Number: C8051F902-GM
• Description: IC MCU 8BIT 8KB FLASH 24QFN
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F9xxr

Specifications of C8051F902-GM

• Program Memory Type: FLASH
• Program Memory Size: 8KB (8K x 8)
• Package / Case: 24-QFN
• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 16
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 0.9 V ~ 3.6 V
• Data Converters: A/D 15x10/12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: C8051F9x
• Core: 8051
• Data Ram Size: 768 B
• Interface Type: UART
• Maximum Clock Frequency: 25 MHz
• Number Of Timers: 4
• Operating Supply Voltage: 0.9 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Development Tools By Supplier: C8051F912DK
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 12 bit
• Package: 24QFN EP
• Device Core: 8051
• Family Name: C8051F90x
• Maximum Speed: 25 MHz
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 16
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1848-5

C8051F91x-C8051F90x
24.1. Signal Descriptions
The four signals used by each SPIn (MOSI, MISO, SCK, NSS) are described below.
24.1.1. Master Out, Slave In (MOSI)
The master-out, slave-in (MOSI) signal is an output from a master device and an input to slave devices. It
is used to serially transfer data from the master to the slave. This signal is an output when SPIn is operat-
ing as a master anSPInd an input when SPIn is operating as a slave. Data is transferred most-significant
bit first. When configured as a master, MOSI is driven by the MSB of the shift register in both 3- and 4-wire
mode.
24.1.2. Master In, Slave Out (MISO)
The master-in, slave-out (MISO) signal is an output from a slave device and an input to the master device.
It is used to serially transfer data from the slave to the master. This signal is an input when SPIn is operat-
ing as a master and an output when SPIn is operating as a slave. Data is transferred most-significant bit
first. The MISO pin is placed in a high-impedance state when the SPI module is disabled and when the SPI
operates in 4-wire mode as a slave that is not selected. When acting as a slave in 3-wire mode, MISO is
always driven by the MSB of the shift register.
24.1.3. Serial Clock (SCK)
The serial clock (SCK) signal is an output from the master device and an input to slave devices. It is used
to synchronize the transfer of data between the master and slave on the MOSI and MISO lines. SPIn gen-
erates this signal when operating as a master. The SCK signal is ignored by a SPI slave when the slave is
not selected (NSS = 1) in 4-wire slave mode.
24.1.4. Slave Select (NSS)
The function of the slave-select (NSS) signal is dependent on the setting of the NSSnMD1 and NSSnMD0
bits in the SPInCN register. There are three possible modes that can be selected with these bits:
See Figure 24.2, Figure 24.3, and Figure 24.4 for typical connection diagrams of the various operational
modes. The setting of NSSMD bits affects the pinout of the device. When in 3-wire master or 3-wire
slave mode, the NSS pin will not be mapped by the crossbar. In all other modes, the NSS signal will be
mapped to a pin on the device. See Section “21. Port Input/Output” on page 205 for general purpose port I/
O and crossbar information.
256
1. NSSMD[1:0] = 00: 3-Wire Master or 3-Wire Slave Mode: SPIn operates in 3-wire mode, and
2. NSSMD[1:0] = 01: 4-Wire Slave or Multi-Master Mode: SPIn operates in 4-wire mode, and
3. NSSMD[1:0] = 1x: 4-Wire Master Mode: SPIn operates in 4-wire mode, and NSS is enabled as
NSS is disabled. When operating as a slave device, SPIn is always selected in 3-wire mode.
Since no select signal is present, SPIn must be the only slave on the bus in 3-wire mode. This
is intended for point-to-point communication between a master and one slave.
NSS is enabled as an input. When operating as a slave, NSS selects the SPIn device. When
operating as a master, a 1-to-0 transition of the NSS signal disables the master function of
SPIn so that multiple master devices can be used on the same SPI bus.
an output. The setting of NSSMD0 determines what logic level the NSS pin will output. This
configuration should only be used when operating SPIn as a master device.
Rev. 1.0