Altera DDR SDRAM High-Performance Controllers and ALTMEMPHY IP - Manual (Page 115)

Chapter 6: Functional Description—High-Performance Controller II 6–21
Example Top-Level File
June 2011 Altera Corporation External Memory Interface Handbook Volume 3
Section I. DDR and DDR2 SDRAM Controllers with ALTMEMPHY IP User Guide
■ Low-power mode operation
The example driver requests the controller to place the memory into power-down
and self-refresh states, and hold it in those states for the amount of time specified
by the COUNTER_VALUE signal. You can vary this value to adjust the duration the
memory is kept in the low-power states. This test is only available if your
controller variation enables the low-power mode option.
The example driver has four outputs that allow you to observe which tests are
currently running and if the tests are passing. The pass not fail (pnf) signal goes low
once one or more errors occur and remains low. The pass not fail per byte
(pnf_per_byte) signal goes low when there is incorrect data in a byte but goes back
high again once correct data is observed in the following byte. The test_status signal
indicates the test that is currently running, allowing you to determine which test has
failed. The test_complete signal goes high for a single clock cycle at the end of the set
of tests.
Table 6–11 shows the bit mapping for each test status.
Table 6–12 shows the ALTMEMPHY Debug interface signals, which are located in
_phy.v/vhd file.
Table 6–11. Test Status[] Bit Mapping
Bit Test
0 Sequential address test
1 Incomplete write test
2 Data mask pin test
3 Address pin test
4 Power-down test
5 Self-refresh test
6 Auto-precharge test
Table 6–12. ALTMEMPHY Debug Interface Signals
Signal Name Direction Description
dbg_clk Input Debug interface clock
dbg_addr Input Debug interface address
dbg_cs Input Debug interface chip select
dbg_wr Input Debug interface write request
dbg_wr_data Input Debug interface write data
dbg_rd Input Debug interface read request
dbg_rd_data Input Debug interface read data
dbg_waitrequest Output Debug interface wait request