Datasheet

161
4341H–MP3–10/07
AT8xC51SND2C/MP3B
19.3.2 Slave Configuration
The SPI operates in slave mode when the MSTR bit in SPCON is cleared and data has been
loaded is SPDAT.
19.3.3 Data Exchange
There are 2 possible methods to exchange data in master and slave modes:
• polling
• interrupts
19.3.4 Master Mode with Polling Policy
Figure 19-9 shows the initialization phase and the transfer phase flows using the polling method.
Using this flow prevents any overrun error occurrence.
The bit rate is selected according to Table 19-1. The transfer format depends on the slave
peripheral.
SS may be deasserted between transfers depending also on the slave peripheral.
SPIF flag is cleared when reading SPDAT (SPSTA has been read before by the “end of transfer”
check).
This polling method provides the fastest effective transmission and is well adapted when com-
municating at high speed with other microcontrollers. However, the procedure may then be
interrupted at any time by higher priority tasks.