Summary of In-Circuit PIC Loader using PIC18F458 microcontroller
This article describes an in-circuit PIC loader connecting a PC printer port to program PIC chips using WinPic800. It utilizes a PIC18F458 microcontroller, a DS1820 temperature sensor, and a 20x4 LCD display for a test board. The hardware includes tristate buffers (U1A, U1B) for signal management and an MC3406A DC-to-DC converter to generate the required +12V programming voltage.
Parts used in the In-Circuit PIC Loader:
- PIC18F458 microcontroller
- DS1820 temperature sensor
- 20x4 LCD display
- Tristate buffer U1A
- Tristate buffer U1B
- MC3406A DC-to-DC converter
- PC printer port interface
- WinPic800 software
This loader connects the PC printer port and works with WinPic800. The loader gets DC supply from application board and provides +12V for high voltage programming mode. We can use it for programming many PIC chips easily.
Hardware Schematic
The In-circuit serial programming for PIC chips requires only three signals, i.e. a bi-directional DATA line (PGD), a synchronize clock (PGC), and a +12V Flash programming voltage (VPP). U1A is a tristate buffer for sending data stream. U1B is for clock stream. Both gates disconnect the signals, PGD and PGC from application board when VDD is turned off. The programming voltage +12V, is generated by DC-to-DC converter, U4 MC3406A. The hardware settings for WinPic800 is compatible with Propic2.
I built the test board with PIC18F458, DS1820 and 20×4 LCD display. Figure 7 shows hardware schematic of the test board. The test program displays temperature from -40C to +150C on LCD. Figure 8 shows code window of PIC18F458.
How to use WinPic800 with PIC loader.
For more detail: In-Circuit PIC Loader using PIC18F458 microcontroller
- How does the loader obtain power?
The loader gets its DC supply from the application board. - What signals are required for In-circuit serial programming?
It requires a bi-directional DATA line, a synchronize clock, and a +12V Flash programming voltage. - Which component generates the +12V programming voltage?
The DC-to-DC converter U4 MC3406A generates the +12V voltage. - Can this loader be used with many PIC chips?
Yes, it can be used for programming many PIC chips easily. - What happens to the PGD and PGC signals when VDD is off?
Both gates disconnect the signals PGD and PGC from the application board when VDD is turned off. - Is the hardware compatible with Propic2?
Yes, the hardware settings for WinPic800 are compatible with Propic2. - What components were used in the test board?
The test board was built with PIC18F458, DS1820, and a 20x4 LCD display. - What temperature range does the test program display?
The test program displays temperature from minus 40C to plus 150C on the LCD.
