OM13008,598 NXP Semiconductors, OM13008,598 Datasheet - Page 213

• Manufacturer Part Number: OM13008,598
• Description: BOARD LPC XPRESSO LPC122X
• Manufacturer: NXP Semiconductors
• Series: LPCXpressor

Specifications of OM13008,598

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 568-6642; OM13008

NXP Semiconductors
UM10441
User manual
11.10.7.1 Simultaneous repeated START conditions from two masters
11.10.7.2 Data transfer after loss of arbitration
11.10.7.3 Forced access to the I
A repeated START condition may be generated in the master transmitter or master
receiver modes. A special case occurs if another master simultaneously generates a
repeated START condition (see
either master since they were both transmitting the same data.
If the I
a repeated START condition itself, it will release the bus, and no interrupt request is
generated. If another master frees the bus by generating a STOP condition, the I
will transmit a normal START condition (state 0x08), and a retry of the total serial data
transfer can commence.
Arbitration may be lost in the master transmitter and master receiver modes (see
Figure
0x78, and 0xB0 (see
If the STA flag in CON is set by the routines which service these states, then, if the bus is
free again, a START condition (state 0x08) is transmitted without intervention by the CPU,
and a retry of the total serial transfer can commence.
In some applications, it may be possible for an uncontrolled source to cause a bus
hang-up. In such situations, the problem may be caused by interference, temporary
interruption of the bus or a temporary short-circuit between SDA and SCL.
If an uncontrolled source generates a superfluous START or masks a STOP condition,
then the I
obtained within a reasonable amount of time, then a forced access to the I
possible. This is achieved by setting the STO flag while the STA flag is still set. No STOP
condition is transmitted. The I
and is able to transmit a START condition. The STO flag is cleared by hardware
Figure
08H
Fig 26. Simultaneous repeated START conditions from two masters
S
2
20). Loss of arbitration is indicated by the following states in STAT; 0x38, 0x68,
27.
C hardware detects a repeated START condition on the I
SLA
2
C-bus stays busy indefinitely. If the STA flag is set and bus access is not
W
All information provided in this document is subject to legal disclaimers.
18H
A
Figure 22
Rev. 1.1 — 10 March 2011
DATA
2
C-bus
2
C hardware behaves as if a STOP condition was received
and
repeated START earlier
Figure
other Master sends
28H
A
Figure
26). Until this occurs, arbitration is not lost by
S
23).
Chapter 11: LPC122x I2C-bus controller
OTHER MASTER
CONTINUES
2
C-bus before generating
retry
08H
P
UM10441
© NXP B.V. 2011. All rights reserved.
S
2
C-bus is
SLA
2
213 of 442
C block