Microchip Technology MCP401XEV, Руководство пользователя

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Installation and Operation
©
2010 Microchip Technology Inc. DS51888A-page 27
2.6 MCP40D18EV DEMO STEPS
This demo assumes that you know how to configure the PICkit Serial Analyzer for
Master I
2
C operation. See Section 2.5 “Configuring The PICkit Serial Analyzer” or
the PICkit Serial Analyzer User’s Guide (DS51647) for additional information.
1. Plug the PICkit Serial device into the PC’s USB port.
2. Plug the MCP40D18EV board into the PICkit Serial.
3. Start the PICkit Serial GUI.
4. Ensure the GUI is in Master I
2
C communication mode (see Figure 2-4).
5. Ensure that the Master I
2
C configuration is appropriately configured (see
Figure 2-6).
6. Measure the wiper voltage on the MCP40D18EV board using an oscilliscope or
digital multimeter. Measure voltage from the ground plane (GND) to the Wiper
(P7). The voltage on the wiper should be ~ V
DD
/2 (~2.5V).
7. Open the Script Builder window (see Figure 2-7).
8. Double click on the “WriteAddrA8” script in the “Example I2CM Scripts column.
This loads the Script Detail column (see Figure 2-9).
9. Modify the “Script Detail” so that it is like that shown in Figure 2-13.
10. Click on the “Execute Script” button. This executes the script shown in the script
detail column, which will update the wiper value to 7Fh. The Wiper voltage will
now be ~V
DD
(~5V). The Transaction window (see Figure 2-15) will be updated
to indicate the execution of the script.
11. Select the “MCP40D18_Read” script in the User I2CM Scripts column. It should
look like Figure 2-14.
12. Click on the “Execute Script” button. This executes the script shown in the script
detail column. The Transaction window (see Figure 2-15) will be updated to
indicate the execution of the script. The Data read is shown in the last line.
13. Select the “MCP40D18_Write” script in the User I2CM Scripts column. It should
look like Figure 2-13.
14. Modify the data value to write to the wiper (see Figure 2-13) to 1Fh.
15. Click on the “Execute Script” button. This executes the script shown in the script
detail column, which will update the wiper value to 1Fh (from 7Fh). The Wiper
voltage will now be ~1/4*V
DD
(~1.25V). The Transaction window (see
Figure 2-16) will be updated to indicate the execution of the script.
16. Select the “MCP40D18_Read” script in the User I2CM Scripts column. It should
look like Figure 2-14.
17. Click on the “Execute Script” button. This executes the script shown in the script
detail column. The Transaction window (see Figure 2-16) will be updated to
indicate the execution of the script. The Data read is shown in the last line.
18. You can repeate the sequence of writing values to the wiper register or Writing
then reading the values back.
NOTICE
If at any time during script execution, an error message is generated in the transaction
window, it is good practice to reset the PICkit Serial Analyzer (PKSA). The PKSA can be
reset using the “Reset” toolbar icon. Verify that subsequent script operations do not
generate errors.