Datasheet

Table Of Contents
FDS 6531/6532 005 Data Sheet 71M6531D/F-71M6532D/F
Rev 2 49
Figure 13: 3-Wire Interface. Read Command.
Figure 14: 3-Wire Interface. Write Command when CNT=0
Figure 15: 3-Wire Interface. Write Command when HiZ=1 and WFR=1
1.5.15 SPI Slave Port
The slave SPI port communicates directly with the MPU data bus and is able to read and write Data RAM
locations. It is also able to send commands to the MPU. The interface to the slave port consists of the
PCSZ, PCLK, PSDI and PSDO pins. These pins are multiplexed with the LCD segment driver pins SEG3
to SEG6. The port pins default to LCD driver pins. The port is enabled by setting the SPE bit.
A typical SPI transaction is as follows. While PCSZ is high, the port is held in an initialized/reset state.
During this state, PSDO is held in HiZ state and all transitions on PCLK and PSDI are ignored. When
PCSZ falls, the port will begin the transaction on the first rising edge of PCLK. A transaction consists of
an 8-bit command, a 16-bit address and then one or more bytes of data. The transaction ends when
PCSZ is raised. Some transactions may consist of a command only.
The last SPI command and address (if part of the command) are available to the MPU in registers
SP_CMD and SP_ADDR.
The SPI port supports data transfers at 1 Mb/s in mission mode and 16 kb/s in BROWNOUT mode. The
SPI commands are described in Table 49 and in Figure 16 illustrate the SPI Interface read and write tim-
ing.
CNT Cycles (8 shown)
READ
D0D1D2D3D4D5
INT5
D6D7
EECTRL Byte Written
SCLK (output)
BUSY (bit)
SDATA (input)
SDATA output Z
(HiZ)
CNT Cycles (0 shown)
Write -- No HiZ
D7
INT5 not issued
CNT Cycles (0 shown)
Write -- HiZ
INT5 not issued
EECTRL Byte Written EECTRL Byte Written
SCLK (output)
BUSY (bit)
SDATA (output)
SCLK (output)
BUSY (bit)
SDATA (output)
(HiZ)
SDATA output ZSDATA output Z
(LoZ)
CNT Cycles (6 shown)
Write -- With HiZ and WFR
EECTRL Byte Written
SCLK (output)
BUSY (bit)
SDATA (out/in)
D2D3D4D5D6D7
BUSY
READY
(From EEPROM)
INT5
(From 6520)
SDATA output Z
(HiZ)(LoZ)