Electrical characteristics
STM32F042x4 STM32F042x6
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DocID025832 Rev 5
SPI/I
2
S characteristics
Unless otherwise specified, the parameters given in
for SPI or in
for I
2
S
are derived from tests performed under the ambient temperature, f
PCLKx
frequency and
supply voltage conditions summarized in
Table 21: General operating conditions
.
Section 6.3.14: I/O port characteristics
for more details on the input/output alternate
function characteristics (NSS, SCK, MOSI, MISO for SPI and WS, CK, SD for I
2
S).
Table 62. I
2
C analog filter characteristics
(1)
1. Guaranteed by design, not tested in production.
Symbol
Parameter
Min
Max
Unit
t
AF
Maximum width of spikes that are
suppressed by the analog filter
50
(2)
2. Spikes with widths below t
AF(min)
are filtered.
260
(3)
3. Spikes with widths above t
AF(max)
are not filtered
ns
Table 63. SPI characteristics
(1)
Symbol
Parameter
Conditions
Min
Max
Unit
f
SCK
1/t
c(SCK)
SPI clock frequency
Master mode
-
18
MHz
Slave mode
-
18
t
r(SCK)
t
f(SCK)
SPI clock rise and fall
time
Capacitive load: C = 15 pF
-
6
ns
t
su(NSS)
NSS setup time
Slave mode
4Tpclk
-
ns
t
h(NSS)
NSS hold time
Slave mode
10
-
t
w(SCKH)
t
w(SCKL)
SCK high and low time
Master mode, f
PCLK
= 36 MHz,
presc = 4
Tpclk/2 -2
Tpclk/2 + 1
t
su(MI)
t
su(SI)
Data input setup time
Master mode
4
-
Slave mode
5
-
t
h(MI)
Data input hold time
Master mode
4
-
t
h(SI)
Slave mode
5
-
t
a(SO)
(2)
Data output access time
Slave mode, f
PCLK
= 20 MHz
0
3Tpclk
t
dis(SO)
(3)
Data output disable time
Slave mode
0
18
t
v(SO)
Data output valid time
Slave mode (after enable edge)
-
22.5
t
v(MO)
Data output valid time
Master mode (after enable edge)
-
6
t
h(SO)
Data output hold time
Slave mode (after enable edge)
11.5
-
t
h(MO)
Master mode (after enable edge)
2
-
DuCy(SCK)
SPI slave input clock
duty cycle
Slave mode
25
75
%
1. Data based on characterization results, not tested in production.
2. Min time is for the minimum time to drive the output and the max time is for the maximum time to validate the data.
3. Min time is for the minimum time to invalidate the output and the max time is for the maximum time to put the data in Hi-Z