8-bit microcontroller with accelerated two-clock 80C51 core
The P89LPC933/934/935/936 provides another high-speed serial communication
interface—the SPI interface. SPI is a full-duplex, high-speed, synchronous
communication bus with two operation modes: Master mode and Slave mode. Up to
3 Mbit/s can be supported in Master mode or up to 2 Mbit/s in Slave mode. It has a
Transfer Completion Flag and Write Collision Flag Protection.
BY 4, 16, 64, 128
SPI clock (master)
8-BIT SHIFT REGISTER
READ DATA BUFFER
SPI STATUS REGISTER
Fig 17. SPI block diagram
SPI CONTROL REGISTER
The SPI interface has four pins: SPICLK, MOSI, MISO and SS:
• SPICLK, MOSI and MISO are typically tied together between two or more SPI
devices. Data flows from master to slave on MOSI (Master Out Slave In) pin and flows
from slave to master on MISO (Master In Slave Out) pin. The SPICLK signal is output
in the master mode and is input in the slave mode. If the SPI system is disabled, i.e.,
SPEN (SPCTL.6) = 0 (reset value), these pins are configured for port functions.
• SS is the optional slave select pin. In a typical configuration, an SPI master asserts
one of its port pins to select one SPI device as the current slave. An SPI slave device
uses its SS pin to determine whether it is selected.
Typical connections are shown in Figure 18 through Figure 20.
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 8 — 12 January 2011
© NXP B.V. 2011. All rights reserved.
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