Alternatively, using a Tally table (see link in my sig) to avoid the loop:

declare @x nvarchar(100)

set @x = 'AZ az' + char(160) + '01' -- note: 160 is an html non breaking space

SELECT

SUBSTRING(@x,N,1), ASCII(SUBSTRING(@x,N,1))

FROM

Tally

WHERE

N <= LEN(@x)