Hello,I am working with a AT25XE081D-MAHN-T via this schematic (note the MX25U8035FZUI is our second choice as this is a low power application).The issue I am seeing is that the device is not entering ultra deep power mode.I can see on the oscilloscope/multimeter that nHOLD, nWP are being held high. I can, also, see that the proper command 0x79 is being sent on the MOSI line. Before the ultra deep power mode command, the ID command, 0x9f, returns the correct ID - after the command, the device returns zeros (expected). The problem is that I am not seeing a reduction in current draw from the device. Before and after the command, the current draw is 90uA.The current is being measured via this circuit:This is my command line log via UART:flash id gets the ID (0x9f).flash write does a dummy write (0x02).flash erase performs a chip erase (0x60).flash read does a read back for the dummy write (0x0b).flash sleep puts the device into ultra deep power mode (0x7f).flash wake takes the device out of UDPM (0xab).Again, I can see my uC sending and receiving properly over the SPI interface.
Hi Tom,You say from your command line log via UART: "flash sleep puts the device into ultra deep power mode (0x7f).">>> But ultra deep power mode command is 0x79 or 0xB9See screenshot of deep power mode commands.
Please see section 6.33 of datasheet.Also, this command is used in conjunction with bit 7 (PDM).Try 0xB9 command. After sending this command CS must be de-asserted. Only then it will enter the Deep Power mode.
Best regardsRenesas Electronics Online Support
Sorry Sarpa,I mistyped previously. I have been using 0x79 as the command for ultra deep power mode. I have, also, tried 0xb9 for ultra deep power mode with PDM bit 7 set low and I have similar results. Similarly, I have tried 0xb9 for deep power mode with PDM bit 7 set high and that saw no current change either.I can see via the scope that the NCS pin is being pushed high.
Hi Tom,Please check if you meet the following conditions:1) The complete opcode must be clocked in before the CS pin is de-asserted, and the CS pin must be de-asserted on a byte boundary (multiples of eight bits); otherwise, the device aborts the operation and returns to the StandbyMode once the CS pin is de-asserted. 2) Also, the device defaults to the Standby Mode after a power-cycle.3) The Deep Power-Down command is ignored if an internally self-timed operation, such as a program or erasecycle, is in progress. The Deep Power-Down command must be reissued after the internally self-timed operationhas been completed in order for the device to enter the Deep Power-Down mode.Confirm that the erase operation in your step "flash erase performs a chip erase (0x60)" was completed before sending the ultra-deep power mode.
In fact, I suggest that you should simply try the ultra-deep power mode right after a normal power RESET (without any other commands or operations).Check to see what the current draw is.
Also, I see you say the following in your screenshot number 2 =>AT25XE081D: Current stand by 50 uA and Current power down 250 nA: what is this about?Best regardsRenesas Electronics Online Support
1. I believe my NCS pin is being deasserted following the entire transaction end. It also appear that this is 8-clock cycles.2. I have attempted this following a power reset and monitored current consumption for the 15 seconds prior, sent the command, and monitored for 15 seconds after and I see no negative edge throughout this time period.3. Prior to sending any command I am checking the NRDY/BUSY bit (BIT0) in the status 1 register to ensure previous commands are completed. 4. The currents listed there are the MAX currents listed in the datasheet for their respective modes. Is there anything else I should check/set/monitor to see the listed current consumption from the device in ultra-deep power mode?
Hi Tom,What is the stand by Current you see in your measurement?(After power-up: That is when the chip is idle and no commands active)
We are seeing 85-90uA and then after being placed into ultra deep sleep we are still seeing 85-90uA.
Hi Tom,If you are seeing a stand by Current (After power-up: That is when the chip is idle and no commands active) of 85-90uA then there is something wrong with the way current is measured or could be a defective part. I say this because, for AT25XE081D the stand by current should be 30uA typical. But you are measuring 3 times that value.
It looks like the INA293A4QDBVRQ1 current sense amplifier is measuring the total current associated with MX25U8035FZUI and AT25XE081D (may be there are other circuit in this path as well?) as per the circuit you show.
Best thing to isolate such issue is as follows:1) Test your (calibrate) INA293A4QDBVRQ1 current sense amplifier part alone with a known (resistive load) current of 30uA.2) After confirming step 1, replace resistive load with AT25XE081D.3) Measure stand by Current (After power-up: That is when the chip is idle and no commands active).4) Verify result with two or three AT25XE081D parts.