Lbu Write To Ertec 400 With Common Read/Write Line (Lbu_Rdy_N Active Low); Figure 15: Lbu Write Sequence With Common Rd/Wr Line; Table 25: Lbu Write Access Timing With Common Read/Write Line - Siemens Ertec 400 Manual

7.3.4

LBU Write to ERTEC 400 with common Read/Write line (LBU_RDY_N active low)

LBU_CS_R_N/
LBU_CS_M_N
LBU_WR_N
LBU_A(20:0)/
LBU_SEG(1:0)/
LBU_BE(1:0)_N
LBU_RDY_N
LBU_D(15:0)

Figure 15: LBU Write Sequence with common RD/WR line

Parameter
t write signal asserted to chip select setup time
WCS
t address valid to chip select asserted setup time
ACS
t chip select asserted to ready enabled delay
CRE
t chip select asserted to data valid delay
CDV
t ready active pulse width
RAP
t write signal deasserted to chip select deasserted hold time
CWH
t address valid to chip select deasserted hold time
CAH
t ready asserted to chip select deasserted delay
RTC
t data valid/enabled to chip select deasserted hold time
CDH
t write recovery time
WR

Table 25: LBU write access timing with common Read/Write line

1
t
The setup time must be maintained under all circumstances; otherwise the LBU unit drives the ERTEC 400
WCS
databus.
The ERTEC 400 has two LBU chip select inputs. One for access to the page configuration register
(LBU_CS_R_N) and one to access to the ERTEC 400 memory address space (LBU_CS_M_N). Only one of
these chip select signals may be active at a time and it is not allowed to chahge the chip select during the
complete access.
The polarity of the signal LBU_RDY_N can be configured using the input LBU_POL_RDY:
LBU_POL_RDY = 0
LBU_POL_RDY = 1
The LBU access control can be configured using the input LBU_CFG:
LBU_CFG = 0 use separate read/write lines (LBU_RD_N and LBU_WR_N)
LBU_CFG = 1 use common read/write lines (LBU_WD_N)
If common read/write line is selected, the unused input LBU_RD_N must be pulled to inactive level with an pull up
resistor.
Copyright © Siemens AG 2010. All rights reserved.
Technical data subject to change
t
WCS
t
ACS
t
CRE
t
CDV
Description
(external pull down resistor used)
(external pull up resistor used)
t
RTC
t
RAP
LBU_RDY_N is LOW active
LBU_RDY_N is HIGH active
Page
80
t
WR
t
CWH
t
CAH
t
CDH
Min Max
1
2 ns
0 ns
5 ns 12 ns
40 ns
17 ns 23 ns
0 ns
0 ns
0 ns
0 ns
25 ns
ERTEC 400 Manual
Version 1.2.2