AN2549 Datasheet, PDF (16/33 Pages) STMicroelectronics – Porting an application from the ST10F269Zx to the ST10F272Z2

AN2549
2
New features
New features
2.1
2.1.1
2.1.2
Additional XPeripherals
Some peripherals have been added to the ST10F272Z2. They are mapped on the XBus and
are linked to additional alternate functions of some ports of the ST10F272Z2.
The additional XPeripherals are the following:
● A second SSC (SSC of ST10F269Zx becomes SSC0, while the new one is referred to
as XSSC or simply SSC1). Note that some restrictions and functional differences due
to the XBus peculiarities are present between the standard SSC, and the new XSSC.
● A second ASC (ASC0 of ST10F269Zx remains ASC0, while the new one is referred to
as XASC or simply as ASC1). Note that some restrictions and functional differences
due to the XBus peculiarities are present between the standard ASC, and the new
XASC.
● An I2C interface is added (see X-I2C or simply I2C interface).
In addition to the previous XPeripherals, the ST10F272Z2 also features a second PWM
(PWM of ST10F269Zx becomes PWM0, while the new one is referred to as XPWM or
simply as PWM1). Note that some restrictions and functional differences due to the XBus
peculiarities are present between the standard PWM, and the new XPWM.
Hardware impact
None if the additional XPeripherals are not used.
Software impact
None if the additional Peripherals are not used. As they are XPeripherals, they can be
enabled / disabled via the XPERCON and SYSCON registers. By default, the settings of
XPERCON and SYSCON are compatible with the ST10F269Zx.
2.2
Programmable divider on CLKOUT
A specific register mapped on the XBus is used to choose the division factor on the
CLKOUT signal (P3.15).
XCLKOUTDIV (E902h)
XBUS
Reset value: --00h
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
Reserved
DIV
-
R/W
Table 12. XCLKOUTDIV register description
Bit
Function
DIV
f_clkout = f_CPU / (DIV + 1)
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