I
2
C Controller
MPC885 PowerQUICC Family Reference Manual, Rev. 2
Freescale Semiconductor
32-11
32.6
I
2
C Commands
The I
2
C transmit and receive commands, shown in
Table 32-8
, are issued to the CPM command register
(CPCR).
32.7
I
2
C Buffer Descriptor (BD) Tables
As shown in
Figure 32-12
, buffer descriptors (BDs) are organized into separate Rx and TxBD tables in
dual-port RAM. The tables have the same basic configuration as for the SCCs and SMCs and form circular
queues that determine the order buffers are transferred. The CPM uses BDs to confirm reception and
transmission or to indicate error conditions so that the core knows buffers have been serviced. The buffers
themselves can be placed in external memory or in any unused parameter area of the dual-port RAM.
Figure 32-12. I
2
C Memory Structure
Table 32-8. I
2
C Transmit/Receive Commands
Command
Description
INIT
TX
PARAMETERS
Initializes all transmit parameters in the parameter RAM to their reset state. Should be issued only
when the transmitter is disabled. The
INIT
TX
AND
RX
PARAMETERS
command can also be used to
reset both the Tx and Rx parameters.
CLOSE
RXBD
Forces the I
2
C controller to close the current Rx BD and use the next BD for subsequently received
data. If the controller is not receiving data, no action is taken. Use this command to extract data from
a partially full buffer.
INIT
RX
PARAMETERS
Initializes all receive parameters in the parameter RAM to their reset state. Should be issued only
when the receiver is disabled. The
INIT
TX
AND
RX
PARAMETERS
command can also be used to reset
both the Tx and Rx parameters.
Status and Control
Data Length
Buffer Pointer
Status and Control
Data Length
Buffer Pointer
Tx Buffer
I2C RxBD Table Pointer
(RBASE)
Rx Buffer
Dual-Port RAM
External Memory
TxBD Table
RxBD Table
Tx Buffer
I2C TxBD Table Pointer
(TBASE)
I2C RxBD Table
I2C TxBD Table
Содержание PowerQUICC MPC870
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Страница 606: ...SDMA Channels and IDMA Emulation MPC885 PowerQUICC Family Reference Manual Rev 2 19 20 Freescale Semiconductor ...
Страница 738: ...SCC Asynchronous HDLC Mode and IrDA MPC885 PowerQUICC Family Reference Manual Rev 2 25 16 Freescale Semiconductor ...
Страница 780: ...SCC Ethernet Mode MPC885 PowerQUICC Family Reference Manual Rev 2 27 24 Freescale Semiconductor ...
Страница 794: ...SCC Transparent Mode MPC885 PowerQUICC Family Reference Manual Rev 2 28 14 Freescale Semiconductor ...
Страница 848: ...Serial Peripheral Interface SPI MPC885 PowerQUICC Family Reference Manual Rev 2 30 18 Freescale Semiconductor ...
Страница 882: ...Universal Serial Bus USB MPC885 PowerQUICC Family Reference Manual Rev 2 31 34 Freescale Semiconductor ...
Страница 944: ...Parallel I O Ports MPC885 PowerQUICC Family Reference Manual Rev 2 34 26 Freescale Semiconductor ...
Страница 956: ...CPM Interrupt Controller MPC885 PowerQUICC Family Reference Manual Rev 2 35 12 Freescale Semiconductor ...
Страница 1004: ...Buffer Descriptors and Connection Tables MPC885 PowerQUICC Family Reference Manual Rev 2 37 30 Freescale Semiconductor ...
Страница 1022: ...ATM Parameter RAM MPC885 PowerQUICC Family Reference Manual Rev 2 38 18 Freescale Semiconductor ...
Страница 1068: ...ATM Pace Control MPC885 PowerQUICC Family Reference Manual Rev 2 40 22 Freescale Semiconductor ...
Страница 1090: ...UTOPIA Interface MPC885 PowerQUICC Family Reference Manual Rev 2 43 8 Freescale Semiconductor ...
Страница 1120: ...AAL2 Implementation MPC885 PowerQUICC Family Reference Manual Rev 2 44 30 Freescale Semiconductor ...
Страница 1162: ...Fast Ethernet Controller FEC MPC885 PowerQUICC Family Reference Manual Rev 2 45 40 Freescale Semiconductor ...
Страница 1172: ...SEC Lite Overview MPC885 PowerQUICC Family Reference Manual Rev 2 46 8 Freescale Semiconductor ...
Страница 1176: ...SEC Lite Address Map MPC885 PowerQUICC Family Reference Manual Rev 2 47 4 Freescale Semiconductor ...
Страница 1214: ...SEC Lite Execution Units MPC885 PowerQUICC Family Reference Manual Rev 2 48 38 Freescale Semiconductor ...
Страница 1312: ...Byte Ordering MPC885 PowerQUICC Family Reference Manual Rev 2 A 8 Freescale Semiconductor ...
Страница 1313: ...MPC885 PowerQUICC Family Reference Manual Rev 2 Freescale Semiconductor B 1 Appendix B Serial Communications Performance TBD ...
Страница 1314: ...Serial Communications Performance MPC885 PowerQUICC Family Reference Manual Rev 2 B 2 Freescale Semiconductor ...
Страница 1320: ...Register Quick Reference Guide MPC885 PowerQUICC Family Reference Manual Rev 2 C 6 Freescale Semiconductor ...
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Страница 1386: ...Revision History MPC885 PowerQUICC Family Reference Manual Rev 2 I 2 Freescale Semiconductor ...