Table of Contents
Advertisement
Philips Semiconductors
2
I
C INTERFACE
2
I
C Status register
This is a read-only register. It contains the status code of I
status codes. When the code is F8H, there is no relevant information available and SI bit is not set. All other 25 status codes
2
correspond to defined I
C states. When any of these states entered, the SI bit will be set. Refer to Table 2 to Table 5 for details.
I2STAT
Address: D9h
Not bit addressable
Reset Source(s): Any reset
Reset Value: 11111000B
BIT
SYMBOL
I2STAT7, 3
STA.4, 0
I2STAT2, 0
-
2
I
C SCL Duty Cycle registers I2SCLH and I2SCLL
When the internal SCL generator is selected for the I
values for registers I2SCLL and I2SCLH to select the data rate. I2SCLH defines the number of PCLK cycles for SCL = high,
I2SCLL defines the number of PCLK cycles for SCL = low. The frequency is determined by the following formula:
Bit Frequency = f
Where f
is the frequency of PCLK.
PCLK
The values for I2SCLL and I2SCLH do not have to be the same; the user can give different duty cycle's for SCL by setting these
two registers. However, the value of the register must ensure that the data rate is in the I
the values of I2SCLL and I2SCLH have some restrictions and values for both registers greater than 3 PCLKs are recommended.
2
Table 1: I
C clock rates selection
I2SCLL
+
CRSEL
7.373 MHz
I2SCLH
6
0
7
0
8
0
9
0
10
0
15
0
25
0
30
0
50
0
60
0
2003 Dec 8
7
STA.4
STA.3
FUNCTION
2
I
C the status code.
These three bits are not used and always set to 0.
Figure 5: I
2
/ (2*(I2SCLH + I2SCLL))
PCLK
Bit data rate (Kbit/sec) at f
3.6865 MHz
-
307
-
263
-
230
-
205
369
184
246
123
147
74
123
61
74
37
61
31
2
C interface. The least three bits are always 0. There are 26 possible
6
5
4
STA.2
STA.1
2
C Status register
C interface by setting CRSEL = 0 in the I2CON register, the user must set
OSC
1.8433 MHz
154
132
115
102
92
61
37
31
18
15
66
User's Manual - Preliminary -
P89LPC920/921/922
3
2
1
STA.0
0
0
2
C data rate range of 0 - 400 kHz. Thus
12 MHz
6 MHz
-
-
-
-
-
375
-
333
-
300
400
200
240
120
200
100
120
60
100
50
0
0
Advertisement
Table of Contents
