82C52 Datasheet, PDF (10/20 Pages) Intersil Corporation – CMOS Serial Controller Interface

82C52
GND
C1 (NOTE)
C2 (NOTE)
IX
82C52
OX
NOTE: C1 = C2 = 20pF For CL = 20pF
C1 = C2 = 47pF For CL = 32pF
FIGURE 10.
82C52 - 80C86 Interfacing
The following example (Figure 11) shows the interface for an
82C52 in an 80C86 system.
Use of the Intersil CMOS Interrupt Controller (82C59A) is
optional and necessary only if an interrupt driven system is
desired.
By using the Intersil CMOS 82C84A clock generator, the
system can be built with a single crystal providing both the
processor clock and the clock for the 82C52. The 82C52 has
special divider circuitry which is designed to supply industry
standard baud rates with a 2.4576MHz input frequency.
Using a 15MHz crystal as shown, results in less than a 2%
frequency error which is adequate for many applications. For
more precise baud rate requirements, a 14.7456MHz crystal
will drive the 80C86 at 4.9MHz and provide the 82C52 with
the standard baud rate input frequency of 2.4576MHz. If
baud rates above 156Kbaud are desired, the OSC output
can be used instead of the PCLK (÷6) output for
asynchronous baud rates up to 1Mbaud.
15MHz
AD0, AD7
80C86
OR
80C88
CHIP SELECT
2
ADDRESS BUS
82C88 IORD
(MAX MODE) IOWR
CSO
D0-D7
A0, A1
SDO
SDI
RD _82C52
WR
INT
CLK INTA
X1 CLK
5MHz
PCLK ^2.5MHz
INT IRX ₃
82C59A
INTA
INTR, DR, TBRE
IX
X2 OSC
82C84A OR
82C85
15MHz
FIGURE 11. 80C86/82C52 INTERFACE
SERIAL
DATA
10
FN2950.3
April 26, 2006