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The MPMC MBX interface port is a slave port that connects directly to the MBX 3D Graphics Core master port. Table A.3 lists the MBX interface port signals.
Table A.3. MBX interface port signals
| Name | Type | Source/ destination | Description |
|---|---|---|---|
| GADDR[28:2] | Input | MBX 3D Graphics Core | This is the MBX 3D Graphics Core memory interface address bus for reads and writes. It is 30 bits wide, and is a 32-bit aligned (word) address. The value on this bus is captured by the MPMC when GTRANS = 1 and GAREADY = 1. If the system does not contain an MMU then the top seven bits are not used, and are tied LOW. |
| GAREADY | Output | MBX 3D Graphics Core | This signal is driven HIGH when the MPMC is ready to receive another transfer from the MBX 3D Graphics Core memory interface controller. |
| GBSTRB[3:0] | Input | MBX 3D Graphics Core | This is a four-bit signal which is a byte mask. A HIGH on the relevant byte mask indicates that the byte is valid. There are certain requestors in the MBX 3D Graphics Core that do read-modify-writes and they have a byte granularity. That is, only one or two bytes are valid and therefore the data in the remaining bytes of a 32-bit SDRAM memory location must be retained. These bits relate directly to the DQM signals found on SDRAM devices. The bits of GBSTRB relate to the bytes of GWDATA as follows: 0 = [7:0] 1 = [15:8] 2 = [23:16] 3 = [31:24]. |
| GDREADY | Output | MBX 3D Graphics Core | This signal is driven HIGH by the MPMC to indicate that the returned data is valid. |
| GRDATA[31:0] | Output | MBX 3D Graphics Core | The read data bus is used to transfer data from the MPMC to the MBX 3D Graphics Core during read operations. The value on this bus is captured by the MBX 3D Graphics Core when GDREADY = 1. |
| GSELCS[7:4] | Input | GXI Decoder | This is the MPMC slave select signal. These signals indicate an access to a particular dynamic memory chip select. |
| GSELG | Input | GXI Decoder | This is the MPMC global slave select signal. This signal indicates an access to memory. |
| GTRANS | Input | MBX 3D Graphics Core | This signal, when HIGH, indicates that the current transfer is valid and that the control signals can be sampled by the slave. |
| GWDATA[31:0] | Input | MBX 3D Graphics Core | The write data bus is used to transfer data from the MBX 3D Graphics Core to the MPMC during write operations. The value on this bus is captured by the MPMC when GTRANS = 1 and GAREADY = 1. |
| GWRITE | Input | MBX 3D Graphics Core | This signal defines whether the current transfer is a read or a write. When LOW it signifies a read. When HIGH it signifies a write. The value of this signal is captured by the MPMC when GTRANS = 1 and GAREADY = 1. |
| Copyright © 2003-2005 ARM Limited. All rights reserved. | ARM DDI 0277F |
| Non-Confidential | |
| PDF version | |
| Home > Signal Descriptions > MBX interface port signals |