AS8168 Ver la hoja de datos (PDF) - austriamicrosystems AG
Número de pieza
componentes Descripción
Fabricante
AS8168
Single Phase Average Energy Metering IC with On-Chip Calibration, Stepper Motor Drive and LED Output
austriamicrosystems AG
AS8168 Datasheet PDF : 30 Pages
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Data Sheet AS8168
Testwrite
Testwrite means that the word to be programmed is simply written to an on-chip shift register so that the resulting behavior of
the AS8168 device may be examined. Once the PROM word is confirmed correct, it may be burned into the device. i.e.
Irreversibly written to the AS8168.
Until the data has been burned into the device, in other words, if only a Testwrite procedure has been performed, the data
will be lost when the supply is removed from the AS8168 device.
Due to the respective on-chip processing it is required to testwrite the inverse of the word to be programmed. Continuing with
the above example the word defined in the example should be as follows:
69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51
1 11 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
50
…
34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19
1
…
1110110101011100
18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1 01 0 1 1 0 0 1 0 0 1 0 1 0 1 1 1 0
The Testwrite procedure is carried out as described in the following timing diagram:
Startup
TM
69
68
67
f1
DIRO
t2
PROG
x
x
define start
testwrite testwrite
mode
(DIRO=0)
H
Imax:
500µA
Note: High and Low refers to VDD and VSS respectively.
4
3
L
H
2
1
t3
H
H
0
High
Low
High
Low
L
3V-3.5V
0V
On the first falling TM edge the mode (Testwrite) is defined. On the next rising TM edge the procedure is started. Afterwards
70 clocks have to be sent to DIRO. As can be seen the logic level on PROG prior to the positive DIRO edges defines the
state to be shifted into the internal register.
Important timing parameters are:
f1: Maximum frequency, must not exceed 50kHz
t2: Data setup time, minimum is 100ns
t3: Data storage time: the programmed bit is stored after approximately 20ns
Burn
The Burn procedure irreversibly writes data to the PROM. To do this, the 1s in the original word to be programmed must be
burned.
Revision 1.2, 11-Feb-05
Page 19 of 30
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