The XMOS SDRAM library is designed for read and write access of arbitrary length 32b long word buffers at up to 62.5MHz clock rates. It uses an optimized pinout with address and data lines overlaid along with other pinout optimizations to implement 16 bit read/writes to Single Data Rate (SDR) SDRAM devices of size up to 256Mb, while consuming a total of just 20 xCORE I/O pins.
The SDRAM component has the following features:
Configurability of:
- SDRAM capacity
- clock rate (62.5 to 25MHz steps are provided)
- refresh properties
Supports:
- read of 32b long words
- write of 32b long words
- one or more clients
- asynchronous command decoupling with a command queue of length 8 for each client
- refresh handled by the SDRAM component itself
Requires a single core for the server
Requires 500MHz core clock operation
- SDRAM server
- Memory address allocator
.. resusage::
:widths: 6 1 4 1 1 1
* - configuration: SDRAM server
- globals: out buffered port:32 sdram_dq_ah=XS1_PORT_16A;out buffered port:32 sdram_cas=XS1_PORT_1B;out buffered port:32 sdram_ras=XS1_PORT_1G;out buffered port:8 sdram_we=XS1_PORT_1C;out port sdram_clk=XS1_PORT_1F;clock sdram_cb=XS1_CLKBLK_1;
- locals: streaming chan c_sdram[1];
- fn: sdram_server(c_sdram, 1,sdram_dq_ah,sdram_cas,sdram_ras,sdram_we,sdram_clk,sdram_cb,2, 128, 16, 8,12, 2, 64, 4096, 4);
- pins: 20
- ports: 4 (1-bit), 1 (16-bit)
* - configuration: Memory address allocator
- globals:
- locals: interface memory_address_allocator_i to_memory_alloc[1];
- fn: memory_address_allocator( 1, to_memory_alloc, 0, 1024*1024*8);
- pins: 0
- ports: 0
.. libdeps::
- I/O Timings for xCORE200 [1].
| [1] | https://www.xmos.com/download/private/I-O-timings-for-xCORE200%281.0%29.pdf |