Shulou(Shulou.com)06/01 Report--

This article mainly explains "what is the use of arm9 IIC interface", interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn "what's the use of the arm9 IIC interface"?

In the use of 2440, its iic interface is generally used to read the data of the peripheral chip. In this case, 2440 is in the host mode. This example describes the host send / receive mode in the way of interrupt.

The process of using the host sending mode:

IICCON: whether to return ack, bus clock selection, interrupt flag

IICCON [7] this bit does not make sense in send mode, because in send mode the host only receives ACK signals and does not actively send out ACK.

In the receiving mode, if the host needs to continue to return data from the slave, it must send an ACK, otherwise the data sender will not continue to send data.

To sum up: no matter it is the master / slave, as long as the receiving party wants to continue to communicate, it must send an ACK signal, so the ACK signal is definitely sent by the receiving party.

IICCON [5] must be 1, otherwise IICCON [4] cannot be used

IICCON [4] 0: no interruption occurs 1: when an interrupt occurs, the bus transmission is aborted. If you want to continue the transmission, you need to clear the bit 0

The conditions for the interruption: 1. Bus arbitration failed 2. Send / receive a byte 3. When the broadcast or slave address match is successful

GPEUP | = 0xc000; / / Internal pull-up GPECON is prohibited | = 0xa0000000; / / Select pin function: GPE15:IICSDA, GPE14:IICSCL INTMSK & = ~ (BIT_IIC) / clear IIC interrupt mask bit / * bit [7] = 1, enable ACK * bit [6] = 0, IICCLK = PCLK/16 * bit [5] = 1, enable interrupt * bit [3:0] = 0xf, Tx clock = IICCLK/16 * PCLK = 50MHz, IICCLK = 3.125MHz, Tx Clock = 0.195MHz * / IICCON = (1

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.