ez80f91 ZiLOG Semiconductor, ez80f91 Datasheet - Page 216

• Manufacturer Part Number: ez80f91
• Description: Ez80 Acclaimplus!? Connectivity Assp Ez80f91 Assp
• Manufacturer: ZiLOG Semiconductor

PS027001-0707
Data Transfer Procedure with SPI Configured as a Slave
SPI Registers
1. Load the SPI BRG Registers, SPI_BRG_H and SPI_BRG_L. The external device
2. Load the SPI Control Register, SPI_CTL.
3. Assert the ENABLE pin of the slave device using a GPIO pin.
4. Load the SPI Transmit Shift Register, SPI_TSR.
5. When the SPI data transfer is complete, deassert the ENABLE pin of the slave device.
The following list describes the procedure for transferring data from a slave SPI device to
a master SPI device.
1. Load the SPI BRG Registers, SPI_BRG_H and SPI_BRG_L.
2. Load the SPI Transmit Shift Register, SPI_TSR. This load cannot occur while the SPI
3. Wait for the external SPI Master device to initiate the data transfer by asserting SS.
There are six registers in the Serial Peripheral Interface that provide control, status, and
data storage functions. The SPI registers are described in the following paragraphs.
SPI Baud Rate Generator Registers—Low Byte and High Byte
These registers hold the Low and High bytes of the 16-bit divisor count loaded by the CPU
for baud rate generation. The 16-bit clock divisor value is returned by {SPI_BRG_H,
SPI_BRG_L}. Upon RESET, the 16-bit BRG divisor value resets to
ured as a Master, the 16-bit divisor value must be between
When configured as a Slave, the 16-bit divisor value must be between
inclusive.
A Write to either the Low- or High-byte registers for the BRG Divisor Latch causes both
bytes to be loaded into the BRG counter and a restart of the count. See
Table 113
must deassert the SS pin if currently asserted.
slave is currently receiving data.
on page 209.
0003h
Product Specification
and
Serial Peripheral Interface
0002h
0004h
FFFFh
Table 112
eZ80F91 ASSP
. When config-
, inclusive.
and
and
FFFFh
,
208