PD243X Datasheet, PDF (2/7 Pages) OSRAM GmbH – Alphanumeric Programmable Display

Figure 1. Block diagram of A/D converter
AN0 – AN7
MUX
ANALOG
I/P
S&H
8-BIT A/D
CONVERTER
8
8-BIT ADDAT
8
REF+
ANALOG VALUE
FOR IVAREF
REF–
ANALOG VALUE
FOR IVAGND
I
VAREF
N
T
E
4-BIT D/A
4-BIT D/A
R
CONVERTER
CONVERTER
N
A
L
VAGND
4
B
4
U
S
MSB
LSB
8-BIT
DAPR
7
6
5
4
3
2
1
0
8
DIGITAL VALUE
DIGITAL VALUE
FOR IVAREF
FOR IVAGND
8-BIT BD CLK – BSY ADM MX2 MX1 MX0
8
ADCON 7 6 5 4 3 2 1 0
Baud System
Rate Clock
Enable Enable
Busy Conver-
Flag sion
Analog Input
Mode
Select
Conversion of the sampled analog voltage takes place between the
6th and 15th machine cycle after sampling has been completed. In
the 15th machine cycle the converted result is moved to ADDAT.
Timer 2
The SAB 80515 has three 16-bit Timer/Counters: Timer 0, Timer 1
and Timer 2. These Timers can be configured to operate either as
Figure 2. Functional diagram of Timer 2 in reload mode
Input
clock
TL2
TH2
T2EX
P 1.5
Mode 1
Mode 0
Reload
CRCL
Low Byte
CRCH
High Byte
Compare/Reload/Capture Register
EXEN 2
TF 2
≥1
EXF 2
Timer 2
Interrupt
Request
timers or event counters. Timer 2 is the time base of the
programmable Timer/Counter Register Array (PTRA) unit.
In addition to the operational modes “Timer” or “counter”,
Timer 2, being the time base for the PTRA unit, provides
the features of:
—16-bit reload
—16-bit compare
—16-bit capture
The reload mode of Timer 2 is used in this application to
generate software delays. For explanation of the other
modes please refer to the users’ manual.
Reload
The reload mode for Timer 2 is selected by bits T2R0 and
T2R1 in special function register T2CON as illustrated in
Table 1. In mode 0, when Timer 2 rolls over from all 1s to
all 0s, it not only sets TF2 but also causes the Timer 2 reg-
isters to be loaded with the 16-bit value in the CRC (com-
pare/reload/capture) register which is preset by software.
The reload will happen in the same machine cycle in which
TF2 is set, thus overwriting the count value 0000H.
Table 1. Timer 2 reload mode selection
T2RI T2R0 Mode
0
X
Reload Disabled
1
0
Mode 0: Auto-Reload upon Timer 2
Overflow (TF2)
1
1
Mode 1: Reload upon Falling Edge at
Pin T2EX/P1.5
PD2435
The PD2435 is a CMOS 4-character 5x7 dot matrix alpha-
numeric programmable display with ROM to decode 128
ASCII alphanumeric characters and enough RAM to store
the display’s complete four digit ASCII message with soft-
ware programmable attributes. The CMOS IC incorporates
special interface control circuitry to allow the user to
control the module as a fully supported microprocessor
peripheral.
Microprocessor Interface
The interface to the microprocessor is through the address
lines (A0-A2), the data bus (D0-D7), two chip select lines
(CE0, CE1), and (RD) and (WR) lines. The CE0 should be
held low and CE1 held high when executing a read or write
to a specific PD243X device. The read and write lines
are both active low. A valid write will enable the data as
input lines.
Programming the PD2435
There are five registers within the PD2435. Four of the reg-
isters are used to hold the ASCII code of the four display
characters. The fifth register is the Control Word, which is
used to blink, blank, clear or dim the entire display to
change the presentation (attributes) of individual
characters.
 2000 Infineon Technologies Corp. • Optoelectronics Division • San Jose, CA
www.infineon.com/opto • 1-888-Infineon (1-888-463-4636)
OSRAM Opto Semiconductors GmbH & Co. OHG • Regensburg, Germany
www.osram-os.com • [phone]
2
Appnote 49
May 31, 2000-14