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Hi, Mike.  We are about to develop a USB connected data logging system with four channels.

The device needs to fit into a mini package, preferably ca. keyfob size and powered from the USB port.

There a a few Microchip products we have looked at but nothing entirely suitable.

Can you suggest best chips to use, please?

Hi Peter , I probably need to know a little bit more about your application , is the logger permanently tethered to the PC/ Master or does it have it's own battery for when untethered , what are you using for memory to store the logged data - or does it smply get passed to the PC. What sort of ADC do you need ? We've recently released a host of new larger memory USB MCUs - you should see them in our 2nd Half Focus Products Guide .

If the logger has it's own lithium cell - we offer USB charge ICs too.

Regards , Mike

Hi Mike,

i have a problem with program EEPROM on dspic 30F3013.

i don't understand why i can program or erase EEPROM

i can read value that i have sent with ICD2

do you know what happen?

you can find my code below!

in debug mode , i can't see the value in NVMKEY ( 0x55 then 0xAA ), and NVMCOM,#WR keep '0'

can you help me !

  mov  #tblpage(posit_P1),w0
  mov  w0,NVMADRU
  mov  #tbloffset(posit_P1),w0
  mov   w0,NVMADR
  call CEEPROM
  MOV  #tblpage(posit_P1),W0
  MOV  W0,TBLPAG
  MOV  #tbloffset(posit_P1),W0
  call EEEPROM

CEEPROM:
  ; Setup NVMCON to erase one word of data EEPROM
  mov  #0x4044,w0
  MOV  w0,NVMCON
  ; Disable interrupts while the KEY sequence is written
  PUSH  SR
  MOV  #0x00E0,W0
  IOR  SR
  ; Write the KEY sequence
  MOV  #0x55,W0
  MOV  W0,NVMKEY
  MOV  #0xAA,W0
  MOV  W0,NVMKEY
  nop
  nop
  ; Start the erase cycle
  BSET  NVMCON,#WR
  nop
  nop
CEE1:
  ; attente fin ecriture
  btsc    NVMCON,#WR
  goto    CEE1  ; Re-enable interrupts
  POP  SR
  return

EEEPROM:
  ; Write data value to holding latch
  TBLWTL  W2,[ W0]
  ; NVMADR captures write address from the TBLWTL instruction.
  ; Setup NVMCON for programming one word to data EEPROM
  MOV  #0x4004,W0
  MOV  W0,NVMCON
  ; Disable interrupts while the KEY sequence is written
  PUSH  SR
  MOV  #0x00E0,W0
  IOR  SR
  ; Write the key sequence
  MOV  #0x55,W0
  MOV  W0,NVMKEY
  MOV  #0xAA,W0
  MOV  W0,NVMKEY
  nop
  nop
  ; Start the write cycle
  BSET  NVMCON,#WR
  nop
  nop
EEE1:
  ; attente fin ecriture
  btsc    NVMCON,#WR
  goto    EEE1
  ;Re-enable interrupts, if needed
  POP  SR
  return

Thanks for the quick response, Mike

Logger permanently connected (when in use), no battery/PSU.

Data constantly passed to PC for processing, only storage necessary if PC doesn't respond in time, (unlikely).

So sufficient storage for 40 16 bit words would be OK.

If the PC can't handle this we'll order a new PC

10 bit ADC is also OK for this app.

The device is only used as and when required and only with PC connected running its own logging/display software.

Battery not needed. Nice idea tho'

Peter

Thanks for the quick response, Mike

Logger permanently connected (when in use), no battery/PSU.

Data constantly passed to PC for processing, only storage necessary if PC doesn't respond in time, (unlikely).

So sufficient storage for 40 16 bit words would be OK.

If the PC can't handle this we'll order a new PC

10 bit ADC is also OK for this app.

The device is only used as and when required and only with PC connected running its own logging/display software.

Battery not needed. Nice idea tho'

Peter