STV9425 STMicroelectronics, STV9425 Datasheet - Page 6

• Manufacturer Part Number: STV9425
• Description: Video ICs On-Screen Disp Montr
• Manufacturer: STMicroelectronics
• Type: Multisync On-Screen Display For Monitorr

Specifications of STV9425

• Maximum Operating Temperature: + 70 C
• Package / Case: DIP-24
• Minimum Operating Temperature: 0 C
• Mounting Style: Through Hole
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

STV9425 - STV9425B - STV9426
FUNCTIONAL DESCRIPTION
The STV9425/25B/26display processor operation
is controlled by a host MCU via the I
is fully programmab le through 16 internal
read/write registers and performs all the display
functions by generating pixels from data stored in
its internal memory. After the page downloading
from the MCU, the STV9425/25B/26 refreshes
screen by its built in processor, without any MCU
control (access).In addition, the host MCU has a
direct access to the on chip 1Kbytes RAM during
the display of the current page to make any update
of its contents.
With the STV9425/25B/26,a page displayed on the
screen is made of several strips which can be of 2
types : spacing or character and which are de-
scribed by a table of descriptors and character
codes in RAM. Several pages can be downloaded
at the same time in the RAM and the choice of the
current display page is made by programming the
CONTROL register.
I - Serial Interface
The 2-wires serial interface is an I
be connected to the I
slave address ; the slave address of t he
STV9425/25B/26is BA (in hexadecimal).
Figure 3 : STV9425/25B/26/I
Figure 4 : STV9425/25B/26/I
6/15
SCL
SDA
SCL
SDA
SCL
SDA
SCL
SDA
A6
Start
Start
D7
Start
A5
D6
D5
A4
Data Byte 1
D4
D3
A3
2
C bus, a device must own its
I
I
I
1
1
2
D2
C Slave Address
C Slave Address
C Slave Address
D1
A2
D0
2
2
C Write Operation
C Read Operation
ACK
R/W
A1
2
C interface. To
2
D7
R/W
C interface. It
R/W
D6
ACK
ACK
A0
ACK
D5
A7
D7
R/W
A7
Data Byte 2
D4
A6
D6
A6
A5
D5
D3
LSB Address
Data Byte 1
A5
A4
D4
D2
LSB Address
A4
I.1 - Data Transfer in Write Mode
T h e h o s t MCU ca n writ e d at a in t o t he
STV9425/25B/26registers or RAM.
To write data into the STV9425/25B/26, after a
start, the MCU must send (Figure 3) :
- First, the I
- The two bytes of the internal address where the
- The successive bytes of data(s).
All bytes are sent MS bit first and the write data
transfer is closed by a stop.
I.2 - Data Transfer in Read Mode
T h e h o st MCU c a n read d at a f ro m th e
STV9425/25B/26registers, RAM or ROM.
To read data from the STV9425/25B/26(Figure 4),
the MCU must send 2 different I
first oneis made of I
bit at low level and the 2 internal address bytes.
The second one is made of I
with R/W bit at high level and all the successive
data bytes read at successive addresses starting
from the initial address given by the first sequence.
A3
D3
D1
for the R/W bit,
MCU wants to write data(s),
1
A3
A2
D2
D0
A2
A1
D1
ACK
0
D0
A0
A1
2
ACK
ACK
C address slave byte with a low level
A0
D7
1
D7
ACK
-
D6
D6
2
-
D5
C slave addressbyte with R/W
-
1
A13 A12 A10 A10 A9
D5
Data Byte n
D4
-
MSB Address
Data Byte n
D4
A13 A12 A11 A10
D3
MSB Address
1
2
D3
C slave address byte
D2
2
D2
C sequences.The
D1
0
D1
D0
A8
D0
ACK
A9
ACK
ACK
1
A8
ACK
Stop
Stop
Stop