TC94A04AFG/AFDG

2005-09-28

13

2.2.3 Setting RAM (ACMP mode)

In ACMP mode, the TC94A04AFG/AFDG does not write data directly to coefficient RAM (CRAM) or offset RAM (OFRAM). In this mode, data must be written

to the interface buffer RAM (IFB-RAM). Then, all the data are updated together in a period of 1 fs.

For example, if a signal flow filter is designed as in the following diagram, unless the K1 to K5 data are batch-updated, the circuit may resonate. The same

applies to the K6 to K10 data.

Using ACMP mode can reduce the noise caused by updating coefficients while the TC94A04AFG/AFDG is operating.

IFB-RAM is 32-word memory. Therefore, data can be updated at one time in units of up to 32-words.

The length of the data field is 2 × n bytes, where n <= 32.

In addition, operation at the time of transmitting other commands, before package rewriting of the data by ACMP mode was completed cannot be guaranteed.

Please set up again after initializing by RST terminal or the initialization command.

MCU-I/F

IFB-RAM

CRAM

Write one by one･･･

Update for 1 fs

K6

K1

K2

K3

K4

K5

K7

K8

K9

K10

+

+

CS

IFDI

IFCK

C3

C2

C5

C4

C7

C6

C1

C0

A3

A2

A5

A4

A7

A6

A1

A0

RA3

RA2

RA5

RA4

RA7

RA6

RA1

RA0

Cn: COMMAND

An: I

2

C address

RAn: RAM-ADDRESS

Dn: Data

(MCU

→)

start

32h

HZ

HZ

HZ

end

RA11

RA10

RA13

RA12

RA15

RA14

RA9

RA8

D11

D10

D13

D12

D15

D14

D9

D8

HZ

HZ

HZ