➦ Programming the 54¢ Micro
➦ Figure 3. First Example Circuit.
➥ Photo 1. The AVRHVP-1 programmer.
power rail. But, the ATtiny10/11 are
the only two AVRs which don’t have
the SPI interface! The only way to
flash them is to use Atmel’s proprietary scheme called High-Voltage
Serial Programming. And this method
is not as simple as using SPI.
Because we want to save money
by using these inexpensive chips, a
new high-voltage (12V) device
programmer has been developed.
THE AVR HIGH-VOLTAGE
➦ Figure 2. Schematic of the AVRHVP-1
Photo 1 shows the constructed
AVR High-Voltage Serial
Programmer (we call it
AVRHVP-1), and it’s schematic
is shown in Figure 2. Primarily
it’s used for the ATtiny10/11, but
it can also program the
ATtiny12 and ATtiny2323/2343
chips, because these devices
support both SPI and the high-voltage method.
The AVRHP-1 programmer
consists of only two chips: an
Atmel 8051-like Flash MCU
(AT89C4051) and a Dallas
Semiconductor RS-232 interface chip, (DS275). The 4051
has 4K bytes of program memory which is barely enough to hold
the firmware for programming
chores and communication with
the host PC. The DS275 is used to
convert RS-232 voltage levels to TTL,
and vice versa.