TINIm390 Verification Module Chipset Reference Design

要約

Designers of real-world signal applications to the Internet will find this application note helpful in understanding the technical features of the TINIm390 Verification Module. Designed around the Dallas Semiconductor DS80C390 microcontroller and DS2502 IEEE MAC address chip to form a reference design for Internet applications. This application note describes the electrical details of this module, from a system overview to the pin descriptions, AC and DC electrical characteristics.

Much of the information contained in this application note is taken from the MxTNI™ Specification and Developer's Guide.

Introduction

The DSTINI1 (TINIm390) Verification Module is an implementation of the TINI-390 Chipset Reference Design and can be used as a development tool for writing embedded web servers. It includes a 10Base-T Ethernet interface, 512kB of flash for critical system code, up to 1MB of static RAM, dual serial ports, a real-time clock (RTC), dual 1-Wire® ports, a CAN bus interface, and exposes the address and data bus of the DS80C390 microcontroller for simple system expansion. This application note provides a technical description of the TINIm390 Verification Module. The Verification Module schematic, bill of materials, and pinout are downloadable from our ftp site.

System Overview

A minimum TINI-390 chipset design must include the DS80C390 microcontroller, flash ROM, RAM, and a DS2502 IEEE MAC address chip. An expanded chipset design like the TINIm390 can include support for many more advanced features. Figure 1 shows a block diagram of the TINIm390 Verification Module.

Figure 1. TINIm390 Verification Module Block Diagram

In addition to the functionality of a minimal chipset design, the TINIm390 also includes these important features:

512kB of flash memory for critical system code
512kB/1MB of NV SRAM
10Base-T Ethernet Controller
RTC
Dual 1-Wire net interfaces
Dual CAN controllers
Dual serial ports (one RS-232 level and one +5V level)
Exposes the microcontroller's address and data busses for parallel I/O expansion
Requires only a single +5V power supply

Memory Description

The memory map specifies where memory and other peripheral devices are decoded in the microcontroller's address space. Figure 2 shows the TINIm390's memory map. It contains three distinct segments of code, data, and peripheral.

The maximum code segment is 1MB, the data segment maximum is 2MB, and the peripheral segment is up to 1MB. If only 512kB of flash ROM exists in the code segment, the starting address of the data segment remains 0x100000. In other words, the starting addresses of the segments always remain as shown in Figure 2.

Figure 2. Memory Map

Memory chips occupy the code and data segments, and other types of devices, including the Ethernet controller and the RTC, occupy the peripheral segment. Additional peripheral devices that support a parallel interface can be mapped in the peripheral space. However, adding hardware in this fashion also adds capacitive loading to either or both the data and address buses (depending on the device). The system designer must be aware of this loading to ensure reliable system operation. See Table 1 for temperature vs. load characteristics. When adding devices on the peripheral space, the address ranges of the Ethernet controller and the RTC must be avoided.

There is also a separate 4MB peripheral area, known as peripheral chip-enable (PCE) space, that can be used to interface large (up to four 1MB) external memory chips or other hardware devices directly to the microcontroller's address and data buses. However, most hardware is mapped in the peripheral segment because the controller can access it more efficiently. If no devices are mapped in the PCE space, the four PCE control pins can be used as general-purpose port pins.

Detailed memory timing diagrams can be found in the DS80C390 data sheet. The MxTNI Runtime Environment uses two cycle active-low PCE0-3 data reads and writes.

Table 1. Typical Temperature vs. Load Characteristics
Number of Loads*	Min Temperature (°C)	Max Temperature (°C)
0	-20	+70
1	-20	+70
2	-20	+70
3	-20	+60
4	-20	+55
5	-20	+50

*A load is characterized as 7pF applied to the address, control, and data lines of a TINIm390-512.

TINIm390 Chipset Components

The TINI-390 chipset is composed of the Maxim components on the TINIm390 Verification Module. These are standard components and can be purchased from Maxim direct. Data sheets for each of the components can be found on our website. The components include the following:

DS80C390 Microcontroller
DS2502-E48 IEEE 1-Wire MAC Address
DS2433 1-Wire Memory
DS1315 Real-Time Clock
DS1321 Nonvolatile RAM Controller

Table 2. Pin Description
Pin	Name	function
1	IN3	TTL Input. Dual-purpose input pin that can be used as DCD for RTS/CTS flow control or as a general-purpose data input pin.
2	IN1	TTL Input. Dual-purpose input pin that can be used as CTS for RTS/CTS flow control or as a general-purpose data input pin.
3–7	GND	Digital Circuit Ground
8	OWIO	1-Wire Input/Output Pin. 1-Wire bus with slew-rate-controlled pulldown, active pullup, ability to switch in V_PP to program EPROM, and ability to switch in VDD through a low-impedance path to program EEPROM or to perform a temperature conversion.
9	V_PP	+12V Supply Input for EPROM Programming (Note 1)
10	CTX	CAN Bus Tx Line or Bidirectional Port Pin
11	CRX	CAN Bus Rx Line or Bidirectional Port Pin
12	active-low CE0	CPU Chip Enable 0 (Note 2)
13	A19	Address Lines (Note 3)
33–36	A7–A4
37–44	A8–A15
54–57	A0–A3
60–62	A16–A18
14	TX1	Serial Port 1 Output TTL
15	XRX1	Serial Port 1 Input TTL
16	Active-low RD	CPU Read Strobe (Note 3)
17	INTOW	Internal 1-Wire Bus (Note 4)
18	SMCRST	Peripheral Reset from CPU
19	TX232	Serial Port 0 Output
20	RX232	Serial Port 0 Input
21	TX	Serial Port 0 Output TTL
22	XRX0	Serial Port 0 Input TTL
23	active low EXTINT	CPU Interrupt Input
24	CPURST	CPU Reset Input (Note 5)
25	DTR232	RS232 CPU Reset Input (Note 6)
26	EN2480	On-Board DS2480B Enable
27	active-low PCE3	Peripheral Chip Enables from CPU (Note 3)
28	active-low PCE2
29	active-low PCE1
30	active-low PCE0
31	active-low CE3	Chip Enable 3 from CPU (Note 3)
32	active-low PSEN	Program Store Enable from CPU (Note 3)
45	active-low RCEO
46–53	D7–D0	Data Lines (Note 3)
58	active-low WR	CPU Write Strobe (Note 3)
59	IN2	TTL Input. This pin can be used as general-purpose input port pin.
63	ETH3	10Base-T Differential Inputs
64	ETH6	10Base-T Differential Inputs
65	ETH2	10Base-T Differential Outputs
66	ETH1	10Base-T Differential Outputs
67–70	V_CC	±5% at 250mA (max), +5V DC (Note 7)
71	OUT1	TTL Output. Dual-purpose output pin that can be used as RTS for RTS/CTS flow control or as a general-purpose data output pin.
72	OUT2	TTL Output. Dual-purpose output pin that can be used as DTR for RTS/CTS flow control or as a general-purpose data output pin.

Note 1: Pin 9 (V_PP) may be connected to +12V DC to allow EPROM programming with the on-board DS2480B. If pin 9 (V_PP) is not used in this manner, it must be connected to V_CC.

Note 2: To execute from the on-board flash ROM, connect active-low CE0 (Pin 12) to active-low RCE0 (Pin 45). If an external boot-up memory is provided, active-low RCE0 must be pulled high (V_CC) to disable the on-board flash ROM or data bus interference could occur. Logic in the active-low CE0 to active-low REC0 path must take care to present minimal delay (< 6ns) to the active-low CE0 signal.

Note 3: Address bus, data bus, and strobe lines are subject to strict loading limitations. Exceeding these limits can cause erratic system operation with on-board as well as off-board resources. Be sure to buffer any signals that will be heavily loaded off-board. Always adhere to the design specifications to assure reliable system operation.

Note 4: The internal 1-Wire bus (INTOW) is a microcontroller port pin that drives the CPU status LED and links to the board's 1-Wire EPROM memory chip that contains the TINIm390's Ethernet MAC address. Other 1-Wire devices may be connected to this bus in the future to convey configuration data to the TINIm390. If this bus is shorted to ground (low) during system boot-up, a Master Clear is invoked. This forces the contents of the SRAM to be reinitialized.

Note 5: CPURST must be taken high (V_CC) and then released to cause a reset of the TINIm390. An active state on the DTR232 (pin 25) also takes this line high. This line is pulled down through a 22kΩ pulldown on-board.

Note 6: The RS232-level DTR control line is used to invoke a TINIm390 reset when asserted. This is to facilitate loaders and diagnostic equipment that must invoke a reset of the board to gain control of the system. This line is pulled to -8V through 22kΩ and has a 0.01µF capacitor filter to prevent cross talk on an open DTR conductor from causing spurious resets of the TINIm390 if this function is not used.

Note 7: MxTNI board power consumption is rated at no more than 250mA.

Absolute Maximum Ratings
Voltage on Any Pin Relative to Ground Except for the Following Pins:	-0.3V to V_CC + 0.3V
V_PP	+14v
INTOW	+14V
RX232	±30V
ETH3, ETH6	+125
ETH2, ETH1	+125
Operating Temperature	-40°C to +85°C
Storage Temperature	-55°C to +85°C
Soldering Temperature	See IPC/JEDEC J-STD-020A

Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods can affect device reliability.

Recommended DC Operating Conditions (T_A= -20°C to +70°C)
Parameter	Symbol	Conditions	Min	Typ	Max	Units
Power Supply Voltage	V_CC		4.75	5.00	5.25	V

DC Electrical Characteristics (V_CC = 4.75 to 5.25V, T_A = -20°C to +70°C.)
Parameter	Symbol	Conditions	Min	Typ	Max	Units
Supply Voltage	V_CC		4.75		5.25	V
Output Low Voltage	V_OL	I_OL = 1.7mA			0.40	V
Output High Voltage	V_OH	-680µA	2.4			V
Input Low Voltage	V_IL		0		0.80	V
Input High Voltage	V_IH		2.2		V_CC	V
Input Leakage Current	I_IL	0.45 < V_IN < V_CC			320	µA
Reset Trip Point	V_RST		4.50		< 4.75	V
Supply Current Active Mode	I_CC			250		mA
Output Low Voltage for Port 3, 5	V_OL1	I_OL = 1.6mA			0.45	V
Output Low Voltage for Port 3, 5	V_OL2	I_OL = 3.2mA			0.45	V
Output High Voltage for Port 3, 5	V_OH1	I_OH = -50µA	2.4			V
Output High Voltage for Port 3, 5	V_OH2	I_OH = -1.5mA	2.4			V
Logic 1-to-0 Transition Current for Port 3, 5	I_L		-300		+300	µA
Input Current for IN1, IN2, IN3	I_IH			+75	+150	µA
Output Low Voltage for OUT1, OUT2	V_OL3	I_OL = 4mA			0.4	V
Output High Voltage for OUT1, OUT2	V_OH3	I_OH = -2mA	2.4			V
Output Leakage Current for OUT1, OUT2	I_OL3	0 < V_IN < V_CC	-10		+10	µA

AC Electrical Characteristics (V_CC = 4.75 to 5.25V, T_A = -20°C to +70°C.)
Parameter	Symbol	Conditions	Min	Typ	Max	Units
External Oscillator Frequency	1/t_CLCL			18.432		MHz
Active-Low PSEN Pulse Width	t_PLPH		0.5 t_MCS - 5			ns
Active-Low PSEN Low to Valid Instruction In	t_PLIV				0.5 t_MCS - 20	ns
Input Instruction Hold after Active-Low PSEN	t_PXIX		0			ns
Input Instruction Float after Active-Low PSEN	t_PXIZ				See MOVX Characteristics	ns
Capacitive Load Presented to External Devices	C_L				90	pF
Expected Data Retention Time	t_DR	(Note 1)	10			years

Note 1: The minimum expected data retention time in the absence of V_CC is 10 years at +25°C.

Note 2: All signals characterized with load capacitance of 80pF except active-low PSEN, active-low RD, and active-low WR with 100pF.

Note 3: Specifications assume a 50% duty cycle for the oscillator.

Note 4: t_MCS is defined as 2 × t_CLCL.

Note 5: The value t_MCS is a function of the machine cycle clock in terms of the processor's input clock frequency. These relationships are described in the Stretch Value Timing table in the DS80C390 data sheet.

Handling Instructions

Handle the TINIm390 as if it were a PC-style memory module. The TINIm390 is designed to be robust, however electrostatic discharge (ESD) precautions should be observed when handling this module. As with any other electronic device with exposed circuitry, the TINIm390 should be stored in an anti-static box. When inserting the TINIm390 into a socket, verify that power is not present. V_CC and GND connections should be checked before applying power. Also, verify that the input power is between 4.75V and 5.25V.