ISA3 Ember, ISA3 Datasheet - Page 91

• Manufacturer Part Number: ISA3
• Description: INSIGHT ADAPTER 3 FOR EM35X
• Manufacturer: Ember

Specifications of ISA3

• Accessory Type: Adapter
• For Use With/related Products: EM35x
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 636-1022

The SPI slave controller supports various frame formats depending upon the clock polarity (SC_SPIPOL), clock
phase (SC_SPIPHA), and direction of data (SC_SPIORD) (see Table 8-6). The SC_SPIPOL, SC_SPIPHA, and
SC_SPIORD bits are defined within the SCx_SPICFG registers.
MST ORD PHA POL Frame Format
1
8.4.3
When the slave select (nSSEL) signal is asserted by the master, SPI transmit data is driven to the output pin
MISO, and SPI data is received from the input pin MOSI. The nSSEL pin has to be asserted to enable the
transmit serializer to drive data to the output signal MISO. A falling edge on nSSEL resets the SPI slave shift
registers.
Characters transmitted and received by the SPI slave controller are buffered in the transmit and receive FIFOs
that are both 4 entries deep. When software writes a character to the SCx_DATA register, it is pushed onto
the transmit FIFO. Similarly, when software reads from the SCx_DATA register, the character returned is
pulled from the receive FIFO. If the transmit and receive DMA channels are used, the DMA channels also write
to and read from the transmit and receive FIFOs.
Characters received are stored in the receive FIFO. Receiving characters sets the SC_SPIRXVAL bit in the
SCx_SPISTAT register, to indicate that characters can be read from the receive FIFO. Characters received
while the receive FIFO is full are dropped, and the SC_SPIRXOVF bit in the SCx_SPISTAT register is set. The
receive FIFO hardware generates the INT_SCRXOVF interrupt, but the DMA register will not indicate the error
The notation xxx means that the corresponding column header below is inserted to form the field name.
0
0
0
0
0
SCx_SPICFG
SC_SPIxxx
0
0
0
0
1
Operation
0
0
1
1
-
1
0
1
0
1
-
Same as above except LSB first instead of MSB first
Table 8-6. SPI Slave Formats
Final
8-16
EM351 / EM357
120-035X-000G