AN2556 Datasheet, PDF (27/35 Pages) STMicroelectronics – Porting an application from the ST10F269Zx to the ST10F273Z4

AN2556
New registers
4.1.2
Note:
Software impacts
In the ST10F273Z4, this register should be programmed by the user before accessing
XRAM2 so that:
● RGSZ defines a 128 Kbyte window size in order to cover the Flash registers and the
XRAM2 area: RGSZ = 1001b.
● RGSAD defines bits 8 to 19 of the window start address that is the Flash registers area:
RGSAD = E00h.
The desired value should be written in XADRS3 register before enabling XRAM2 in
SYSCON and XPERCON registers.
XADRS3 cannot be changed after executing the EINIT instruction.
4.2
4.2.1
4.2.2
XPEREMU register
This register has been added as a write-only register.
ST10F273Z4: XPEREMU (EB7Eh)
XREG
Reset value: XXXXh
15 14 13 12 11 10 9 8 7
6 54
3
2
10
Reserved
XMIS
CEN
X12
CEN
XSS
CEN
XAS
CEN
XPW
MEN
Res
XRT
CEN
XRA XRA
M2EN M1EN
CAN
2EN
CAN
1EN
-
WO WO WO WO WO - WO WO WO WO WO
The bit meaning is exactly the same as in the XPERCON register.
Hardware impacts
None.
Software impacts
Once the XPEN bit of SYSCON register is set and at least one of the X-peripherals (except
memories) is activated, the register XPEREMU must be written with the same content of
XPERCON. This is mandatory in order to allow a correct emulation of the new set of
features introduced on X-Bus for the new ST10 generation. The following instructions must
be added inside the initialization routine:
– If (SYSCON.XPEN && (XPERCON & 0x07D3))
– Then {XPEREMU = XPERCON}
Of course, XPEREMU must be programmed after XPERCON and after SYSCON, in such a
way the final configuration for X-Peripherals is stored in XPEREMU and used for the
emulation hardware setup.
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