Technical data

BIOS and System Programming
CP 486 ⋅ 00/14 VIPA GmbH 71
4.3.8 Bank Interface
4.3.8.1 Operating Modes of Bank Interface
The bank interface on the CP486 consists of a 8 KByte RAM memory, which can be written or read
from the PLC as well as from the CP side. Memory access and memory size are adjusted via
registers on the CP486 side. Following operating modes are available:
Operating Banks via Bank Selection Register:
In this mode of operation the individual banks are selected via the bank select register on the PLC
side. The bank select register (address 0FEFF(hex)), has a width of 8 bytes and this way supports
256 bank numbers. In this mode the interrupt to the CP3/4 is released, as soon as a write access to
the highest bank byte from the SPS ensues. (Annotation: This mode can only be utilized in address
area 0Fxxx(hex) on the PLC side.)
Operating Banks via the Highest Bank Address:
In this mode of operation the individual banks are selected each via the highest bank byte of the
current bank on the PLC side. So the highest byte of each bank has two functions in this mode of
operation: If the data bit 7 equals 0 during writing, a bank 0..127 (corresponding to the data bits
0..6) will be selected. If bit 7 is set to 1, the bank will not be switched but the value will be stored in
the highest bank byte and an interrupt on the CP486 will be released. When the highest bank byte is
read, always the contents will be returned (annotation: in this mode of operation only 128 bank
numbers are available).
Linear Operation
In linear mode of operation a bank is available to th PLC. A selection of banks is not possible. In
this mode of operation the ident register must have a value of 0 and the number of banks has to be
set to 1. In this mode of operation an interrupt will also be initiated during write access of the PLC
to the highest bank address.
During starting up of the system the BIOS adjusts the default bank operating. In this adjustment 8
banks with a size of 1KByte each are available on the PLC side. The 8 banks are located directly
one after another and will be selected from the PLC via the bank select register. The bank numbers
can be adjusted in the SETUP of the CP486. These 8 banks are available as large continuous
8 KByte memory area on the CP486 side.
For different configurations the registers have to be reparameterized on the CP486 side
correspondingly. These registers are set up the following way: