This output is high output is high when a PTV is indicated to Horizontal center axis.
HBLK-PH Output
Pin 41 is used to adjust the phase of the horizontal blanking .
EPROM/MTP (I002)
The device located in position I002 is used to store the program code needed by the microcontroller to operate the
television correctly. This 32 pin device is an MTP (multi-time programmable memory) which allows for it to be
re-programmed out of the chassis without having to erase it using conventional UV EPROM erasers. The device currently
used on the UP91 chassis is the AT49F002T, which can hold 256Kbytes of information (2Mbit). This device also holds any
initialisation data to be downloaded to an EEPROM. When a blank EEPROM is fitted, the initialisation data is automatically
downloaded to it when power is applied to the chassis.
Supply/Ground Connections
Pins 32 and 16 are the +5V supply and ground connections respectively. The supply voltage of +5V is always present even
when the TV is in the standby state.
Address Connections
Pins 2 to 12, 23 and 25 to 29 are the 17 address lines needed to access the full 256Kbytes of 8-bit data inside the device.
These lines are connected directly with the microcontroller so that it can request data from the MTP when operating. An
oscilloscope can be used to check pin 12 of the MTP to check whether the microcontroller is running correctly and
accessing the MTP. This pin should be oscillating at a frequency of around 2MHz and is a non-periodic square waveform.
Data Connections
Pins 13 to 15 and 17 to 21 are the 8 data lines needed to transmit a byte at a time to the microcontroller. These outputs
are normally tri-state and are high-impedance when the output enable pin 24 of the MTP is HIGH. When the output enable
pin is low, the data from the required address will be output on these pins.
Output Enable Connection
Pin 24 is the output enable active low input used to control the logical state of the data lines. When this pin is HIGH, the
data lines are in the high impedance condition and no data is present on these pins. When the output enable input it LOW,
the data lines are active and output the addressed data, This line is connected to the data strobe output of the
microcontroller to ensure correct operation/timings.
Chip Enable Connection
Pin 22 is the chip enable active low input used to select the device. Normally, this input is low to enable the device.
However, the device can be placed in a standby state when accessing a future SRAM in position I003. The MMU3 line
from the microcontroller is used to select either the SRAM or the MTP. When no SRAM is fitted, the chip enable pin is
always low. |
ACEC
