MC68HC711E20CFN2

Manufacturer Part NumberMC68HC711E20CFN2
DescriptionIC MCU 20K 2MHZ OTP 52-PLCC
ManufacturerFreescale Semiconductor
SeriesHC11
MC68HC711E20CFN2 datasheets
 

Specifications of MC68HC711E20CFN2

Core ProcessorHC11Core Size8-Bit
Speed2MHzConnectivitySCI, SPI
PeripheralsPOR, WDTNumber Of I /o38
Program Memory Size20KB (20K x 8)Program Memory TypeOTP
Eeprom Size512 x 8Ram Size768 x 8
Voltage - Supply (vcc/vdd)4.5 V ~ 5.5 VData ConvertersA/D 8x8b
Oscillator TypeInternalOperating Temperature-40°C ~ 85°C
Package / Case52-PLCCLead Free Status / RoHS StatusContains lead / RoHS non-compliant
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
Page 201
202
Page 202
203
Page 203
204
Page 204
205
Page 205
206
Page 206
207
Page 207
208
Page 208
209
Page 209
210
Page 210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
Page 204/242

Download datasheet (2Mb)Embed
PrevNext
Allowing for Bootstrap Mode
In systems where the PD0/RxD pin is normally used as a general-purpose output, a serial signal from the
host can be connected to the pin without resulting in output driver conflicts. It may be important to consider
what the existing logic will do with the SCI serial data instead of the signals that would have been
produced by the PD0 pin. In systems where the PD0 pin is used normally as a general-purpose input, the
driver circuit that drives the PD0 pin must be designed so that the serial data can override this driver, or
the driver must be disconnected during the bootstrap download. A simple series resistor between the
driver and the PD0 pin solves this problem as shown in
can then be connected to the PD0/RxD pin, and the series resistor will prevent direct conflict between the
host driver and the normal PD0 driver.
EXISTING
CONTROL
TxD Pin
The bootloader program uses the PD1/TxD pin to send verification data back to the host computer. To
minimize the possibility of conflicts with circuitry connected to this pin, port D is configured for wire-OR
mode by the bootloader program during initialization. Since the wire-OR configuration prevents the pin
from driving active high levels, a pullup resistor to V
In systems where the PD1/TxD pin is normally used as a general-purpose output, there are no output
driver conflicts. It may be important to consider what the existing logic will do with the SCI serial data
instead of the signals that would have been produced by the PD1 pin.
In systems where the PD1 pin is normally used as a general-purpose input, the driver circuit that drives
the PD1 pin must be designed so that the PD1/TxD pin driver in the MCU can override this driver. A simple
series resistor between the driver and the PD1 pin can solve this problem. The TxD pin can then be
configured as an output, and the series resistor will prevent direct conflict between the internal TxD driver
and the external driver connected to PD1 through the series resistor.
Other
The bootloader firmware sets the DWOM control bit, which configures all port D pins for wire-OR
operation. During the bootloading process, all port D pins except the PD1/TxD pin are configured as
high-impedance inputs. Any port D pin that normally is used as an output should have a pullup resistor so
it does not float during the bootloading process.
204
Figure
CONNECTED ONLY DURING
FROM
BOOTLOADING
HOST
SYSTEM
RS232
LEVEL
SHIFTER
SIGNAL
SERIES
RESISTOR
EXISTING
DRIVER
Figure 5. Preventing Driver Conflict
is needed if the TxD signal is used.
DD
M68HC11 Bootstrap Mode, Rev. 1.1
5. The serial data from the host computer
MC68HC11
RxD/PD0
(BEING USED
AS INPUT)
Freescale Semiconductor