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diff --git a/md/writeup/stm32f4_sdram_configuration.md b/md/writeup/stm32f4_sdram_configuration.md new file mode 100644 index 0000000..0ea866c --- /dev/null +++ b/md/writeup/stm32f4_sdram_configuration.md @@ -0,0 +1,268 @@ +title: DSP Low-pass FIR filter +keywords:c,stm32,stm32f4,sdram,configuration,timing + +# STM32F4 sdram configuration + +Here is some notes about playing with SDRAM. Some parts are still unclear for +me but looks like all code works. + +STM32 F4 family have build in FMC controller that can be configured to use +SDRAM with easy. + +F4 have 2 internals banks and memory ranges where SDRAM could be configured. + +## SDRAM parametrs + +## STM32 SDRAM FMC params + +STM32F4 SDRAM FMC(Flexible Memory Controller) have many parametrs that allow +to confgiure SDRAM, depending on chip you can have more or less memory avaliable +different clock speeds. + + +| Struct field name | Possible values | Comments | +|---|---|---| +| SDBank | BANK1,BANK2 | | +| ColumnBitsNumber | 8-11 bits | | +| RowBitsNumber | 11-13 bits | | +| MemoryDataWidth | 8,16,32 bits | | +| CASLatency | 1,2,3 | | +| WriteProtection | ENABLE,DISABLE | | +| SDClockPeriod | DISABLE, PERIOD2, PERIOD3 | If system clock 180Mhz then CLK speeds 90Mhz or 60Mhz | +| ReadBurst | ENABLE,DISABLE | | +| ReadPipeDelay | DELAY_0, DELAY_1, DELAY_2 | | + + +## Configure FMC SDRAM timings + +Timing configuration configured in FMC_SDTR1 register + +| Struct field name | RegisterPossible Values | Register bit names | +|---|---|---| +| LoadToActiveDelay | 1-16 cycles | TMRD | +| ExitSlefRedreshDelay | 1-16 cycles | TXSR | +| SelfRefreshTime | 1-16 cycles | TRAS | +| RowCycleDelay | 1-16 cycles | TRC | +| WriteRecoveryTime | 1-16 cycles | TWR | +| RPDelay | 1-16 cycles | TRCD | +| RCDelay | 1-16 cycles | TRC | + +## SDRAM initialisation + +Before SDRAM could start working it need to be configured and commended are +sended. Command are just setting up appropriate bits and wait of 100ms. + +Commands for configure SDRAM + +| Command | Desc | +|---|---| +| FMC_SDRAM_CMD_CLK_ENABLE | Configure a clock configuration enable command | +| FMC_SDRAM_CMD_PALL | Configure a PALL (precharge all) command | +| FMC_SDRAM_CMD_AUTOREFRESH_MODE | Configure a Auto-Refresh command | +| FMC_SDRAM_CMD_LOAD_MODE | Program the external memory mode register | + +```c + FMC_SDRAM_CommandTypeDef Command; + + __IO uint32_t tmpmrd =0; + /* Step 3: Configure a clock configuration enable command */ + Command.CommandMode = FMC_SDRAM_CMD_CLK_ENABLE; + Command.CommandTarget = FMC_SDRAM_CMD_TARGET_BANK1; + Command.AutoRefreshNumber = 1; + Command.ModeRegisterDefinition = 0; + + /* Send the command */ + HAL_SDRAM_SendCommand(hsdram, &Command, 0x1000); + + /* Step 4: Insert 100 ms delay */ + HAL_Delay(100); + + /* Step 5: Configure a PALL (precharge all) command */ + Command.CommandMode = FMC_SDRAM_CMD_PALL; + Command.CommandTarget = FMC_SDRAM_CMD_TARGET_BANK1; + Command.AutoRefreshNumber = 1; + Command.ModeRegisterDefinition = 0; + + /* Send the command */ + HAL_SDRAM_SendCommand(hsdram, &Command, 0x1000); + + /* Step 6 : Configure a Auto-Refresh command */ + Command.CommandMode = FMC_SDRAM_CMD_AUTOREFRESH_MODE; + Command.CommandTarget = FMC_SDRAM_CMD_TARGET_BANK1; + Command.AutoRefreshNumber = 4; + Command.ModeRegisterDefinition = 0; + + /* Send the command */ + HAL_SDRAM_SendCommand(hsdram, &Command, 0x1000); + + /* Step 7: Program the external memory mode register */ + tmpmrd = (uint32_t)SDRAM_MODEREG_BURST_LENGTH_2 | + SDRAM_MODEREG_BURST_TYPE_SEQUENTIAL | + SDRAM_MODEREG_CAS_LATENCY_3 | + SDRAM_MODEREG_OPERATING_MODE_STANDARD | + SDRAM_MODEREG_WRITEBURST_MODE_SINGLE; + + Command.CommandMode = FMC_SDRAM_CMD_LOAD_MODE; + Command.CommandTarget = FMC_SDRAM_CMD_TARGET_BANK1; + Command.AutoRefreshNumber = 1; + Command.ModeRegisterDefinition = tmpmrd; + + /* Send the command */ + HAL_SDRAM_SendCommand(hsdram, &Command, 0x1000); + + HAL_SDRAM_ProgramRefreshRate(hsdram, 0x56A-20); +``` + +### Command list for AS4C16M16SA + +| Commands | +|---| +| BankActive | +| BankPrecharge | +| PrechargeAll | +| Read | +| Read and AutoPrecharge | +| Write | +| Write and AutoPrecharge | +| Mode Register Set | +| No-Operation | +| Burst Stop | +| Devaise Deselect | +| AutoRefresh | +| SelfRefresh Entry | +| SelfRedresh Exit | +| Clock Suspend Mode Entry / PowerDown Mode Entry | +| Clock Suspend Mode Exit / PowerDown Mode Exit | +| Data Write / Output Enable | + +## Calculate parametrs + +### AS4C16M16SA chip parametrs + +Configuration for SystemClock=180Mhz and SDRAM clock rate 90Mhz. +Some values are adjusted to work. + +<math xmlns="http://www.w3.org/1998/Math/MathML"> +<mtable class="m-equation-square" displaystyle="true" style="display: block; margin-top: 1.0em; margin-bottom: 2.0em"> + <mtr> + <mtd> + <mspace width="6.0em" /> + </mtd> + <mtd columnalign="left"> + <mfrac linethickness="1"> + <mn>1</mn> + <mrow> + <mn>90</mn> + <mi>M</mi> + <mi>h</mi> + <mi>z</mi> + </mrow> + </mfrac> + <mo>=</mo> + <mn>11.1</mn> + <mi>u</mi> + </mtd> + </mtr> +</mtable> +</math> + +All resulting values are rounded up. + +| Param in Datasheet | Param | Calc(cycles) | +|---|---|---| +| 12u | TMRD | 1(1.1)+2 ???| +| tRC+tIS = 61.5u | TXSR | 6(5.5)+1 ???| +| 42u | TRAS | 4(3.8)+1 ???| +| 60u | TRC | 6(5.5) | +| 12u | TWR | 2(1.1) | +| 18u | TRP | 2(1.6) | +| 18u | TRCD | 2(1.6) | + +This what worked for me, so should be right (maybe) + +Configuration for SystemClock=180Mhz and SDRAM clock rate 60Mhz + +<math xmlns="http://www.w3.org/1998/Math/MathML"> +<mtable class="m-equation-square" displaystyle="true" style="display: block; margin-top: 1.0em; margin-bottom: 2.0em"> + <mtr> + <mtd> + <mspace width="6.0em" /> + </mtd> + <mtd columnalign="left"> + <mfrac linethickness="1"> + <mn>1</mn> + <mrow> + <mn>60</mn> + <mi>M</mi> + <mi>h</mi> + <mi>z</mi> + </mrow> + </mfrac> + <mo>=</mo> + <mn>16.6</mn> + <mi>u</mi> + </mtd> + </mtr> +</mtable> +</math> + +| Param in Datasheet | Param | Calc(cycles) | +|---|---|---| +| 12u | TMRD | 1(1.1)+2 ???| +| tRC+tIS = 61.5u | TXSR | 4(3.6)+1 ???| +| 42u | TRAS | 3(2.5) | +| 60u | TRC | 4(3.6)+1 ???| +| 12u | TWR | 1(0.8) | +| 18u | TRP | 1(1.1) | +| 18u | TRCD | 1(1.1) | + +### Calculate refresh rate + +From datasheet - 8192 refresh cycles/64ms + +64ms/8192 = 7.8u + +7.8u \* (90Mhz) = 702 +7.8u \* (60Mhz) = 402 + +## Example config + +Here is example config for AS4C16M16SA + +```c + SDRAM->Init.SDBank = FMC_SDRAM_BANK2; + SDRAM->Init.ColumnBitsNumber = FMC_SDRAM_COLUMN_BITS_NUM_9; + SDRAM->Init.RowBitsNumber = FMC_SDRAM_ROW_BITS_NUM_13; + SDRAM->Init.MemoryDataWidth = FMC_SDRAM_MEM_BUS_WIDTH_16; + SDRAM->Init.InternalBankNumber = FMC_SDRAM_INTERN_BANKS_NUM_4; + SDRAM->Init.CASLatency = FMC_SDRAM_CAS_LATENCY_3; + SDRAM->Init.WriteProtection = FMC_SDRAM_WRITE_PROTECTION_DISABLE; + SDRAM->Init.SDClockPeriod = FMC_SDRAM_CLOCK_PERIOD_2; // 90Mhz + SDRAM->Init.ReadBurst = FMC_SDRAM_RBURST_DISABLE; + SDRAM->Init.ReadPipeDelay = FMC_SDRAM_RPIPE_DELAY_1; + + /* Timing configuration for 90 MHz of SDRAM clock frequency (180MHz/2) */ + SDRAM_Timing->LoadToActiveDelay = 2; + SDRAM_Timing->ExitSelfRefreshDelay = 7; + SDRAM_Timing->SelfRefreshTime = 4; + SDRAM_Timing->RowCycleDelay = 7;//was 7 + SDRAM_Timing->WriteRecoveryTime = 2; + SDRAM_Timing->RPDelay = 2; + SDRAM_Timing->RCDDelay = 2; +``` + +## Using SDRAM + +```c +for (i = 0; i < SDRAM_SIZE; i++) { + *(__IO uint16_t*) (SDRAM_BANK_ADDR + 2*i) = (uint16_t)0x00; + } +``` + +Example of setting values into SDRAM. Accessing just like usual memory. + +## Links + +1. [AS4C16M16SA datasheet](https://www.alliancememory.com/wp-content/uploads/pdf/dram/256Mb-AS4C16M16SA-C&I_V3.0_March%202015.pdf) +2. [STM32F429ZI description](http://www.st.com/en/microcontrollers/stm32f429zi.html) +3. [http://en.radzio.dxp.pl/stm32f429idiscovery/sdram.html](http://en.radzio.dxp.pl/stm32f429idiscovery/sdram.html)
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