Siemens ERTEC200 - Manual (Page 82)

7.5.4 LBU Write to ERTEC 200 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
LBU_D(15:0)
t
WCS
t
ACS
t
CRE
t
CDV
t
CDH
t
CAH
t
CWH
t
RTC
t
RAP
t
WR
Figure 16: LBU-Write-Sequence with common RD/WR line
Parameter Description Min Max
t
WCS
write signal asserted to chip select setup time 2 ns
1
t
ACS
address valid to chip select asserted setup time 0 ns
t
CRE
chip select asserted to ready enabled delay 5 ns 12 ns
t
CDV
chip select asserted to data valid delay 40 ns
t
RAP
ready active pulse width 17 ns 23 ns
t
CWH
write signal deasserted to chip select deasserted hold time 0 ns
t
CAH
address valid to chip select deasserted hold time 0 ns
t
RTC
ready asserted to chip select deasserted delay 0 ns
t
CDH
data valid/enabled to chip select deasserted hold time 0 ns
t
WR
write recovery time 25 ns
Table 28: LBU Write access timing with common Read/Write line
1
The setup time t
WCS
must be maintained under all circumstances; otherwise the LBU unit drives the ERTEC 200
databus.
The ERTEC 200 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 200 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 change the chip select during the complete access.
7.6 Host Interrupt Handling:
The ERTEC 200 generates 2 interrupt signals, LBU_IRQ0_N and LBU_IRQ1_N, to the external host. Both interrupts are
generated in the IRT switch interrupt controller. Both signals are set by default to Low Active. However, they can also be
assigned different parameters in the IRT switch.
Mailbox handling between the ARM946E-S and an external host is possible via the IRT switch interrupt controller.
An interrupt request from the ARM946E-S to the host processor is initiated by writing to the Activate_HP_Interrupt
register.
An interrupt request from the host processor to the ARM946E-S is initiated by writing to the Activate_SP_Interrupt
register.
Both registers can only be written to. Any value can be written.
Copyright © Siemens AG 2007. All rights reserved. 82 ERTEC 200 Manual
Technical data subject to change Version 1.1.0