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Is ISD4002 sound recorder IC compatible with Basis Stamp 2 — Parallax Forums

Is ISD4002 sound recorder IC compatible with Basis Stamp 2

thangngocthangngoc Posts: 23
edited 2010-09-25 08:00 in BASIC Stamp
Hi, I would like to know whether the ISD4002 sound recorder IC which has a SPI interface, would work with Basic Stamp 2? Otherwise I have to use PIC micro chip. Thanks

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2010-09-24 20:14
    An ISD4002 should work with a Basic Stamp. The only issue is that the ISD4002 is a 3.3V device while the Basic Stamp is a 5V device. The ISD4002's SPI control and data lines are 5V tolerant as long as the available current is limited to < 20mA. The easiest thing to do is to put a series resistor in each of the lines going between the ISD4002 and the Stamp (MOSI, MISO, SClk, /SS). Anything from 220 Ohms up through 4.7K would work. I'd suggest 1K resistors. There's a long "sticky" thread on the Propeller Forum on using the Propeller (a 3.3V device) with 5V devices. All the things discussed apply to your situation as well.

    Remember that the ground (Vss) lines have to all be in common.
  • thangngocthangngoc Posts: 23
    edited 2010-09-25 07:04
    Thanks for the reply! Can you give me the link to that sticky thread because I couldn't find it? If Iam using the the ISD4002 with the Stamp, which pins from the Stamp associated with MOSI, MISO, SClk, /SS because it doesn't have the SPI interface? Thanks
  • Mike GreenMike Green Posts: 23,101
    edited 2010-09-25 08:00
    The sticky thread is the "Getting Started and Key Thread Index". Look under "Technical Considerations" about 1/3 of the way down.

    There are all sorts of examples of SPI usage with other devices using the SHIFTIN and SHIFTOUT statements. Nuts and Volts Column #33 is one example of the use of a DS1302 Real Time Clock (look here). In this example, the DS1302 uses the same line for MISO and MOSI since they're never both active at the same time. I don't remember if that's also true for the ISD4002, but, if not, just use two I/O pins, one for each, and use the appropriate pin number for the SHIFTIN and SHIFTOUT statements.
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