XMC™ Forum Discussions

Best regards,
I made a PCB containing SDRAM IS42S16400J, connected to microcontroller XMC4700 F144K1536. Wiring is direct copy from XMC4500 hexagon board. There are also some other components, but not on the same pins as RAM ofcourse.

I started testing RAM with original code from "XMClib v2.2.0 - XMC Peripheral Driver Library" that has been sent to me by LinglingG_46  as part of his answer to my question on link https://community.infineon.com/t5/DAVE/SDRAM-in-Dave-ver-4/m-p/401175#M6559 .

The only thing that I added is DAVE init code at the beginning of int main method:

DAVE_STATUS_t status;
status = DAVE_Init();
if (status != DAVE_STATUS_SUCCESS)
{
  XMC_DEBUG("DAVE APPs initialization failed\n");
  while(1U){ }
}

I have quite a few problems convincing RAM to work:

1.: Getting 16 bit only:

Writing and reading RAM sometimes dont work at all, but when it does, it does it "partialy". Let me elaborate:

• I write a value, let's say "0x87654321" to some memory location
• When I read it back, i get "0x87658765" - the first 16 bits are repeated in last 16 bits.
• I believe that there is something wrong with timing on the line that tells RAM which part of data should be on lines AD[15:0]

I susspect that some timing is not correct, but there is so much different settings that I'm totaly lost. Will return to that.

2.: 16 bits work "sometimes"

So, just to be able to continue, I changed part of test program so that it checks only first 16 bits.

I also converted status to error counter.
To "disperse" values in RAM I mutiplied "i" with some big prime called "factor" (also on writing :))

for (i = 0; i < TEST_SIZE ; i++)
{
    mem_add = SDRAM_BASE + (4 * i);
    value = *(volatile uint32_t *)(mem_add);
    if ((value & 0xffff0000) != ((i * factor) & 0xffff0000))
    {
        //status = 1;
        status ++;
    }
}

Running this code repeatedly, I get somewhere arround 660.000 error, out of 2.097.152 samples (approx 1/3rd of time). But error rate is not consistent... 666890, 666594, 656867.

3.: Number of errors HIGHLY depends on DAVE code

This is probbably the funiest part:
If I just remark "DAVE init code" (everything in my first code snippet), I have only 3-5 errors.

And in this case errors are on exact memory addresses:

• 0x60000000 - first location in RAM
• 0x60200000 - at 1/4 of address space
• 0x60400000 - at 2/4 of address space
• 0x60600000 - at 3/4 of address space - not always

I don't know the fifth address, becouse i NEVER get 5 errors, if I have breakpint in line "status ++;"

Let me emphasyse that this testing code is the only thing in test project.

There is no Dave aps in this project. No "digital pins". No pins in "Manual pin mapping" no pins in "Pin Mapping perspective". Only other pins that are used in project are :

#define LED_R P1_10
#define LED_G P1_11
#define LED_SDCARD_R P0_11
#define LED_SDCARD_G P0_6

4.: My suspections

I higly suspect that there is somethnig wrong with timing. Maybe processor is working to fast, or something else is wrong?!?

I must addmit that I don't quite understand communication with SDRAM on low hardware level. I hoped that code from library will work and that I won't have to study RAM on hardware level.
While seraching for solution, I read alot, including entire EBU section in ReferenceManual of XMC4700. I tried different settings in code (section below). Most of settings didn't work at all, some setings didn't change anything.

I also tried with another PCB (I have two prototypes completley assembled). Second one works similary, but with much more errors.

Right now I'm clueless.

5.: SDRAM_CLK_B

Another detail got my attention: in both circuits, "XMC4500 hexagon" and "4800 Automation", there is a RAM pin CLK connected to two pins on microprocessor:

• directly to P5_8 as SRAM_CLK
• via 22E resistor to pin P6_4 as SDRAM_CLK_B

While first one is used in code, "SDRAM_CLK_B" is nowhere to be find. Is this OK?

6.: Conclusion:

As I said, I'm clueless right now.
I do not have a propeper measurement equipment at my hand, so I can't preform electical measurements. But i suspect somethinh in software anyhow.

Any help will be appreciated.

Thanx in advance and best regards to all,

Martin

Apendix: Settings part of code from library.

I think that here I should somehow "slow down" communication with RAM. Here I tried many things without success - Source: "XMClib v2.2.0 - XMC Peripheral Driver Library"

XMC_EBU_t *const ebumodule = (XMC_EBU_t *)EBU;

XMC_EBU_CONFIG_t ebuobj =
{
.ebu_clk_config.ebu_div2_clk_mode = XMC_EBU_DIV2_CLK_MODE_ON,
.ebu_mode_config.ebu_arbitration_mode = XMC_EBU_ARB_MODE_SOLE_MASTER_MODE,
.ebu_free_pins_to_gpio.address_pins_gpio = 0x1ff,
.ebu_free_pins_to_gpio.adv_pin_gpio = false
};


XMC_EBU_REGION_t ebureadwriteconfig =
{

.read_config.ebu_region_no = 0x0U,
.read_config.ebu_bus_read_config.ebu_burst_length_sync = XMC_EBU_BURST_LENGTH_SYNC_8_DATA_ACCESSES,
.read_config.ebu_bus_read_config.ebu_byte_control = XMC_EBU_BYTE_CONTROL_FOLLOWS_CONTROL_SIGNAL_TIMMING,
.read_config.ebu_bus_read_config.ebu_burst_flash_clock_feedback = XMC_EBU_BURST_FLASH_CLOCK_FEEDBACK_ENABLE,
.read_config.ebu_bus_read_config.ebu_device_addressing_mode = XMC_EBU_DEVICE_ADDRESSING_MODE_16_BITS,
.read_config.ebu_bus_read_config.ebu_device_type = XMC_EBU_DEVICE_TYPE_SDRAM,
.read_config.ebu_bus_read_config.address_cycles = 0xFU,
.read_config.ebu_bus_read_config.address_hold_cycles = 0xFU,
.read_config.ebu_bus_read_config.command_delay_lines = 0xFU,
.read_config.ebu_bus_read_config.ebu_ext_data = 0x0U,
.read_config.ebu_bus_read_config.ebu_freq_ext_clk_pin = 0x0U,
.read_config.ebu_bus_read_config.ebu_recovery_cycles_between_different_regions = 0xFU,
.read_config.ebu_bus_read_config.ebu_recovery_cycles_after_read_accesses = 0x7U,
.read_config.ebu_bus_read_config.ebu_programmed_wait_states_for_read_accesses = 0x4U,

.write_config.ebu_region_no = 0x0U,
.write_config.ebu_bus_write_config.ebu_burst_length_sync = XMC_EBU_BURST_LENGTH_SYNC_8_DATA_ACCESSES,
.write_config.ebu_bus_write_config.ebu_byte_control = XMC_EBU_BYTE_CONTROL_FOLLOWS_CONTROL_SIGNAL_TIMMING,
.write_config.ebu_bus_write_config.ebu_device_type = XMC_EBU_DEVICE_TYPE_SDRAM,
.write_config.ebu_bus_write_config.address_cycles = 0xFU,
.write_config.ebu_bus_write_config.address_hold_cycles = 0xFU,
.write_config.ebu_bus_write_config.command_delay_lines = 0xFU,
.write_config.ebu_bus_write_config.ebu_ext_data = 0x0U,
.write_config.ebu_bus_write_config.ebu_freq_ext_clk_pin = 0x0U,
.write_config.ebu_bus_write_config.ebu_recovery_cycles_between_different_regions = 0xFU,
.write_config.ebu_bus_write_config.ebu_recovery_cycles_after_write_accesses = 0x7U,
.write_config.ebu_bus_write_config.ebu_programmed_wait_states_for_write_accesses = 0x4U,
};

XMC_EBU_SDRAM_CONFIG_t ebusdramcontrol =
{
.ebu_sdram_clk_mode= XMC_EBU_SDRAM_CLK_MODE_CONTINUOUSLY_RUNS, /**< SDRAM clock mode select */
.ebu_sdram_mask_for_bank_tag = XMC_EBU_SDRAM_MASK_FOR_BANK_TAG_ADDRESS_22_to_21, /**< Mask for Bank Tag */
.ebu_sdram_mask_for_row_tag = XMC_EBU_SDRAM_WIDTH_OF_COLUMN_ADDRESS_8_to_0, /**< Mask for Row Tag */
/**< Row cycle time counter: Insert (CRCE * 😎 + CRC + 1 NOP cycles */
.ebu_sdram_row_cycle_time_counter = 0x5UL,
/**< (CRCD) Number of NOP cycles between a row address and a column address: Insert CRCD + 1 NOP cycles */
.ebu_sdram_row_to_column_delay_counter = 0x01U,
/**< Number of address bits from bit 0 to be used for column address */
.ebu_sdram_width_of_column_address = XMC_EBU_SDRAM_WIDTH_OF_COLUMN_ADDRESS_8_to_0,
/**< (CRP) Number of NOP cycles inserted after a precharge command: Insert CRP + 1 NOP cycles */
.ebu_row_precharge_time_counter= 0x1U,
/**< (CRSC) Number of NOP cycles after a mode register set command: Insert CRSC + 1 NOP cycles */
.ebu_mode_register_set_up_time = 0x0U,
/**< (CRFSH) Number of refresh commands issued during powerup init sequence: Perform CRFSH + 1 refresh cycles */
.ebu_init_refresh_commands_counter = 0x0AU,
/**< Number of clock cycles between row activate command and a precharge command */
.ebu_row_precharge_delay_counter = 0x03U,
.ebu_sdram_burst_length = XMC_EBU_SDRAM_BURST_LENGTH_1_LOCATION,
.ebu_sdram_casclk_mode = 0x3U,
.ebu_sdram_cold_start = 0x1U,
.ebu_sdram_self_refresh_exit = true,
.ebu_sdram_num_refresh_counter_period = 0x2U,
.ebu_sdram_num_refresh_cmnds = 0x1U,
.ebu_sdram_auto_refresh = 0x1U,
.ebu_sdram_self_refresh_exit_delay = 0xFFU,
.ebu_sdram_auto_self_refresh = 0x01U,
.ebu_sdram_delay_on_power_down_exit = 0x07U
};