HT16515 Ver la hoja de datos (PDF) - Holtek Semiconductor
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HT16515 Datasheet PDF : 13 Pages
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HT16515
Functional Description
Display RAM and Display Mode
The static display RAM stores the data transmitted from
an external device to the HT16515 through a serial inter-
face. The contents of the RAM are directly mapped to
the contents of the VFD driver. Data in the RAM can be
accessed through the data setting, address setting and
display control commands. It is assigned as addresses
in 8-bit unit as follows:
S E G 1 S E G 4 S E G 8 S E G 12 S E G 16 S E G 20 S E G 24
00H L 00H U
03H L 03H U
06H L 06H U
09H L 09H U
01H L
04H L
07H L
0A H L
01H U
04H U
07H U
0A H U
02H L
05H L
08H L
0B H L
0 2 H U D IG 1
0 5 H U D IG 2
0 8 H U D IG 3
0 B H U D IG 4
0C H L
0FH L
12H L
15H L
18H L
1B H L
1E H L
21H L
0C H U
0FH U
12H U
15H U
18H U
1B H U
1E H U
21H U
0D H L
10H L
13H L
16H L
19H L
1C H L
1FH L
22H L
0D H U
10H U
13H U
16H U
19H U
1C H U
1FH U
22H U
0E H L
11H L
14H L
17H L
1A H L
1D H L
20H L
23H L
0E H U
11H U
14H U
17H U
1A H U
1D H U
20H U
23H U
D IG 5
D IG 6
D IG 7
D IG 8
D IG 9
D IG 1 0
D IG 1 1
D IG 1 2
b0 b3b4
b7
XXHL XXHU
L o w e r H ig h e r
4 b its 4 b its
Dimming Control
HT16515 provides an 8-step dimmer function on display
by controlling the 3-bit binary command code. The full
pulse width of grid signal is divided into 16 uniform sec-
tions by PWM (pulse width modulation) technology.
The 16 uniform sections available form an 8-step dim-
mer via 3-bit binary code. The 8-step dimmer includes
1/16, 2/16, 4/16, 10/16, 11/16, 12/16, 13/16 and 14/16.
The 1/16 pulse width indicates minimum lightness. The
14/16 pulse width represents maximum lightness (Refer
to the display control command).
Key Matrix and Key-Input Data Storage RAM
The key matrix scans the series key states at each level
of the key strobe signal (Seg1/K1~Seg16/K16) output of
the HT16515. The key strobe signal outputs are
time-multiplexed signals from Seg1/K1~Seg16/K16. The
states of inputs K0 and K1 are sampled by strobe signal
Seg1/K1~Seg16/K16 and latched into the register.
The key matrix is made up of a 16´2 matrix, as shown
below.
The data of each key is stored as illustrated below, and
is read with the read command, starting from the least
significant bit.
K ey1 K ey2
S 1 /K 1
S 5 /K 5
S 9 /K 9
S 1 3 /K 1 3
b0 b1
K ey1 K ey2
S 2 /K 2
S 6 /K 6
S 1 0 /K 1 0
S 1 4 /K 1 4
b2 b3
K ey1 K ey2
S 3 /K 3
S 7 /K 7
S 1 1 /K 1 1
S 1 5 /K 1 5
b4 b5
K ey1 K ey2
S 4 /K 4
S 8 /K 8
S 1 2 /K 1 2
S 1 6 /K 1 6
b6 b7
R e a d in g S e q u e n c e
LED Port
The LED port is of the CMOS output configuration.
Data is written to the LED port with the write command,
starting from the least significant bit. In our application
(see application circuits), the user adopts an internal
NMOS device to a driver LED component by connecting
VDD. When a bit of this port is 0, the corresponding LED
lights up; when the bit is 1, the LED turns off. The data of
bits 4 through 7 are ignored.
M SB
LS B
b3 b2 b1 b0
LE D 0
D o n 't c a r e
LE D 1
LE D 2
LE D 3
Commands
Commands set the display mode and status of the VFD
driver.
The first 1 byte input to the HT16515 through the DI pin
after the CS pin has fallen, is regarded as a command. If
CS is set high while commands/data are transmitted,
serial communication is initialized, and the commands/
data being transmitted are not valid (however, the com-
mands/data previously transmitted remains valid).
· Display mode setting commands
These commands initialize the HT16515 and select
the number of segments and the number of grids
(1/4~1/12 duty, 16 to 24 segments).
When these commands are executed, the display is
forcibly turned off, and key scanning is also stopped.
To resume display, the display command ²ON² must
be executed. If the same mode is selected, nothing
happens.
S 1/ S 2/ S 3/ S 4/ S 5/ S 6/ S 7/ S 8/ S 9/ S 10/ S 11/ S 12/ S 13/ S 14/ S 15/ S 16/
K1
K2
K3
K4
K5
K6
K7
K8
K9
K 10 K 11 K 12 K 13 K 14 K 15 K 16
KEY1
KEY2
Rev. 1.70
6
May 7, 2010
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