DATA STRUCTURES WITHIN THE RAM (Continued)

The coding of the five control words depends on the mode of the service channel. Using the slave mode

(SCMASTER = 0) they have the following structure:

Index

Bit

Name

Function

0

0

HS_AT

Handshake bit in AT

1

BUSY_AT

Busy bit in AT, also waiting for microprocessor interaction

2

ERR_AT

Error bit in AT

3

Error bit in AT

Command modification bit in AT

4-6

ELEM

Data element of present transmission

7

L/S

Read (0)/write (1) of present transmission

8-9

NINFO_WRITE

Number of info words in write buffer (1 to 4)

10-11

(Not used)

12

INT_ELEM_CHANGE

Master has modified data element or read/write

13

INT_END_WRBUF

End of write buffer is reached

14

INT_END_RDBUF

End of read buffer is reached

15

INT_END_MDT

Master reports end via END_MDT-bit

1

0

HS_MDT

Handshake bit in MDT

1

L/S_MDT

Read/write in MDT

2

END_MDT

End bit in MDT

3-5

ELEM_MDT

Data element in MDT

6

(Not used)

7

RECERR

Last transmission was correct (0) or errorneous (1)

8-9

NINFO_READ

Number of info words in read buffer (1 to 4)

10-15

(Not used)

2

0-7

WRDATPT

Pointer to present position in write buffer

8-15

WRDATLAST

Pointer to last position in write buffer

3

0-7

RDDATPT

Pointer to present position in read buffer

8-15

RDDATLAST

Pointer to last position in read buffer

4

0-8

(Not used)

9

INT_SC_ERR

Interrupt due to protocol error

10-15

(Not used)

®

SERCON410B

28/30