9
ispMACH 4000ZE Pico Development Kit
Lattice Semiconductor
User’s Guide
Run the I
2
C GPIO Expansion Demo
These instructions highlight the LC4256ZE providing general-purpose I/O for an I/O-constrained microprocessor or
DSP. A host PC running the Lattice PicoView program emulates a processor reading and writing I
2
C traffic to I
2
C
slaves embedded in the LC4256ZE and POWR6AT6 devices. The CPLD integrates Verilog-based I
2
C slave and
LCD Controller reference designs to translate the traffic to parallel interfaces of the Pico board. The I
2
C interface to
the POWR6AT6 allows you to monitor voltage or current of various Pico board power supplies.
1.
If not already connected, follow the earlier procedures to connect the Pico board and reprogram it. The USB
cable must be attached and powered to enable the Pico board I
2
C channel and JTAG programming interface.
2.
Start a command prompt and run the PicoView program (c:\4000ze-pico-kit\picoview.exe).
PicoView provides a push-button interface to provide read or read/write access to the registers of the
LC4256ZE and POWR6AT6 devices. When PicoView initializes, all device registers are read and the dialog is
refreshed. A column of “R” and “W” buttons provide read or read/write control over individual registers of the
LC4256ZE. See Figure 5 for details.
3.
Choose
Options > Control Register
. The Control Register dialog appears.
4.
From the Counter/Shift Control section of the dialog select
Count Down/Shift Right
, from the LCD Display
section, select
Shift Register
, and then click
OK
. The Control Register box is updated with value 0x14h.
5.
Click the
Control Register W
button. PicoView writes the control settings to the Pico board to initiate the
embedded shift register and display the results to the LCD panel.
6.
From the ispPAC-POWR6AT6 section of the dialog, select
VMON1 – Core Current
and click the
Read
button.
PicoView updates the POWR6AT6 Register with the core current in microamp units.
Figure 6. PicoView Screen Shot
