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UM10211
NXP Semiconductors
Chapter 19: LPC2300 I2C0, I2C1, I2C2
8.5 Miscellaneous states
There are two I2STAT codes that do not correspond to a defined I2C hardware state (see
Table 19–412). These are discussed below.
19.8.5.1
I2STAT = 0xF8
This status code indicates that no relevant information is available because the serial
interrupt flag, SI, is not yet set. This occurs between other states and when the I2C block
is not involved in a serial transfer.
19.8.5.2
I2STAT = 0x00
This status code indicates that a bus error has occurred during an I2C serial transfer. A
bus error is caused when a START or STOP condition occurs at an illegal position in the
format frame. Examples of such illegal positions are during the serial transfer of an
address byte, a data byte, or an acknowledge bit. A bus error may also be caused when
external interference disturbs the internal I2C block signals. When a bus error occurs, SI is
set. To recover from a bus error, the STO flag must be set and SI must be cleared. This
causes the I2C block to enter the “not addressed” slave mode (a defined state) and to
clear the STO flag (no other bits in I2CON are affected). The SDA and SCL lines are
released (a STOP condition is not transmitted).
UM10211_1
User manual
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 6 July 2007
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