I
2
C Modules
MCF5253 Reference Manual, Rev. 1
Freescale Semiconductor
18-3
of the I
2
C pull-up resistors will need to be kept at a relatively low impedance, which may cause noise
issues in some systems.
The I
2
C system is a true multimaster bus including collision detection and arbitration that prevents data
corruption if two or more masters attempt to control the bus simultaneously. This feature allows for
complex applications with multiprocessor control. It can also be used for rapid testing and alignment of
end products using external connections to an assembly line computer.
18.3
I
2
C System Configuration
I
2
C module uses a serial data line (SDA) and a serial clock line (SCL) for data transfer. All devices
connected to these two signals must have open drain or open collector outputs. The logic AND function is
exercised on both lines with external pullup resistors.
The default state of I
2
C is as a slave receiver out of reset. Thus, when not programmed to be a master or
responding to a slave transmit address, the I
2
C module should always return to the default state of slave
receiver.
NOTE
This I
2
C module is designed to be compatible with the I
2
C bus protocol
from Philips. For further information on I
2
C system configuration, protocol,
and restrictions please refer to the Philips I
2
C Standard.
18.4
I
2
C Protocol
A standard communication is composed of four parts:
1. START signal
2. Slave address transmission
3. Data transfer
4. STOP signal
They are described briefly in the following sections and shown in
Summary of Contents for MCF5253
Page 1: ...Document Number MCF5253RM Rev 1 08 2008 MCF5253 Reference Manual...
Page 26: ...MCF5253 Reference Manual Rev 1 xxvi Freescale Semiconductor...
Page 32: ...MCF5253 Reference Manual Rev 1 xxxii Freescale Semiconductor...
Page 46: ...MCF5253 Introduction MCF5253 Reference Manual Rev 1 1 14 Freescale Semiconductor...
Page 62: ...Signal Description MCF5253 Reference Manual Rev 1 2 16 Freescale Semiconductor...
Page 98: ...Instruction Cache MCF5253 Reference Manual Rev 1 5 10 Freescale Semiconductor...
Page 104: ...Static RAM SRAM MCF5253 Reference Manual Rev 1 6 6 Freescale Semiconductor...
Page 128: ...Synchronous DRAM Controller Module MCF5253 Reference Manual Rev 1 7 24 Freescale Semiconductor...
Page 144: ...Bus Operation MCF5253 Reference Manual Rev 1 8 16 Freescale Semiconductor...
Page 176: ...System Integration Module SIM MCF5253 Reference Manual Rev 1 9 32 Freescale Semiconductor...
Page 198: ...Analog to Digital Converter ADC MCF5253 Reference Manual Rev 1 12 6 Freescale Semiconductor...
Page 246: ...DMA Controller MCF5253 Reference Manual Rev 1 14 18 Freescale Semiconductor...
Page 282: ...UART Modules MCF5253 Reference Manual Rev 1 15 36 Freescale Semiconductor...
Page 344: ...Audio Interface Module AIM MCF5253 Reference Manual Rev 1 17 46 Freescale Semiconductor...
Page 362: ...I2 C Modules MCF5253 Reference Manual Rev 1 18 18 Freescale Semiconductor...
Page 370: ...Boot ROM MCF5253 Reference Manual Rev 1 19 8 Freescale Semiconductor...
