psf21911 ETC-unknow, psf21911 Datasheet - Page 94

• Manufacturer Part Number: psf21911
• Description: Isdn Echocancellation Circuit Terminal Applications Iec-q
• Manufacturer: ETC-unknow

Semiconductor Group
2.9
Important: This chapter applies only in stand-alone mode.
A power controller interface is implemented in the PSB 21911 to provide comfortable
access to peripheral circuits which are not connected directly to the microprocessor .
Because this interface was specifically designed to support the ISDN Exchange Power
Controller IEPC (PEB 2025) it is referred to as “Power Controller Interface”. Despite this
dedication to the IEPC, the controller interface is just as suited for other general-purpose
applications.
Interface Bits (PCD, PCA, PCRD, PCWR, INT)
The interface structure is adapted to the register structure of the IEPC. It consists of three
data bits PCD0 ... 2, two address bits PCA0,1, read and write signals PCRD and PCWR
respectively as well as an interrupt facility INT.
The address bits are latched, they may therefore in general interface applications be
used as output lines. For general interface inputs each of the three data bits is suitable.
Read and write operations are performed via MON-8 commands. Three inputs and two
outputs are thus available to connect external circuitry.
The interrupt pin is edge sensitive. Each change of level at the pin INT will initiate a C/I-
code “INT” (0110
resulting actions need to be performed by the control unit.
Table 21 lists all MON-8- and C/I-commands that are relevant to the power controller
interface.
Table 21
Channel
MON-8
MON-8
MON-8
C/I
Power Controller Interface
MON-8 and C/I-Commands
Code
WCI
RCI
ACI
INT
B
) lasting for four IOM-frames. Interpretation of the interrupt cause and
Function
Write to interface. Address and data is contained in the MON-
command. The address is latched, data is not latched.
Read from interface at specified address. Address is latched
and the current value of the data port is read. The result is
returned to the user with MON-8 “ACI”.
Answer from interface. After a RCI-request the value of three
data bits at the specified address is returned.
Interrupt. After a change of level has been observed, the C/I-
code “INT” is issued for 4 IOM-frames. Note the special timing
of the interrupt signals described on page 96.
94
Power Controller Interface
PSB 21911
PSF 21911
11.97